Add an example of a plugins mechanism

Part of #2035, investigating how we might implement the upcoming LiveObjects SDK as a plugin to the core SDK. The code here is consumed by the following proof of concepts: - LiveObjects plugin [1] - demonstrates how to consume the APIs that this commit exposes - LiveObjects example [2] - demonstrates how a user would use the LiveObjects plugin [1] /~https://github.com/lawrence-forooghian/ably-cocoa-liveobjects-plugin [2] /~https://github.com/lawrence-forooghian/ably-cocoa-liveobjects-example
ably · Feb 25, 2025 · c624de3 · c624de3
1 parent 0da2fec
commit c624de3
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Showing 13 changed files with 197 additions and 6 deletions.
diff --git a/Ably.podspec b/Ably.podspec
@@ -20,6 +20,12 @@ Pod::Spec.new do |s|
   s.resource_bundles        = {'Ably' => ['Source/PrivacyInfo.xcprivacy']}
   s.private_header_files    = 'Source/PrivateHeaders/**/*.h', 'Source/SocketRocket/**/*.h'
   s.module_map              = 'Source/Ably.modulemap'
+  # This is for the import of `APLivePlugin.h` to resolve. Copied from:
+  # - https://stackoverflow.com/questions/28425765/add-a-user-header-search-path-to-a-podspec
+  # - https://stackoverflow.com/questions/58690010/including-a-directory-as-a-search-path-during-compilation-with-cocoapods
+  s.pod_target_xcconfig     = {
+    'HEADER_SEARCH_PATHS' => '"${PODS_TARGET_SRCROOT}/AblyPlugin/include"'
+  }
   s.dependency 'msgpack', '0.4.0'
   s.dependency 'AblyDeltaCodec', '1.3.3'
 end
diff --git a/Ably.xcodeproj/project.pbxproj b/Ably.xcodeproj/project.pbxproj
@@ -368,6 +368,9 @@
 		21AC0CD52D4AA3200030BD23 /* ARTWrapperSDKProxyRealtimeChannels.m in Sources */ = {isa = PBXBuildFile; fileRef = 21AC0CD12D4AA3200030BD23 /* ARTWrapperSDKProxyRealtimeChannels.m */; };
 		21AC0CD62D4AA3200030BD23 /* ARTWrapperSDKProxyRealtimeChannel.m in Sources */ = {isa = PBXBuildFile; fileRef = 21AC0CD02D4AA3200030BD23 /* ARTWrapperSDKProxyRealtimeChannel.m */; };
 		21AC0CD72D4AA3200030BD23 /* ARTWrapperSDKProxyRealtimeChannels.m in Sources */ = {isa = PBXBuildFile; fileRef = 21AC0CD12D4AA3200030BD23 /* ARTWrapperSDKProxyRealtimeChannels.m */; };
+		21BFC2D62D67C58800C05E8B /* ARTRealtimeChannel+Plugins.h in Headers */ = {isa = PBXBuildFile; fileRef = 21BFC2D52D67C58800C05E8B /* ARTRealtimeChannel+Plugins.h */; settings = {ATTRIBUTES = (Private, ); }; };
+		21BFC2D72D67C58800C05E8B /* ARTRealtimeChannel+Plugins.h in Headers */ = {isa = PBXBuildFile; fileRef = 21BFC2D52D67C58800C05E8B /* ARTRealtimeChannel+Plugins.h */; settings = {ATTRIBUTES = (Private, ); }; };
+		21BFC2D82D67C58800C05E8B /* ARTRealtimeChannel+Plugins.h in Headers */ = {isa = PBXBuildFile; fileRef = 21BFC2D52D67C58800C05E8B /* ARTRealtimeChannel+Plugins.h */; settings = {ATTRIBUTES = (Private, ); }; };
 		21E1C0E52A0DC47400A5DB65 /* ARTWebSocketFactory.h in Headers */ = {isa = PBXBuildFile; fileRef = 21E1C0E42A0DC47400A5DB65 /* ARTWebSocketFactory.h */; settings = {ATTRIBUTES = (Private, ); }; };
 		21E1C0E62A0DC47400A5DB65 /* ARTWebSocketFactory.h in Headers */ = {isa = PBXBuildFile; fileRef = 21E1C0E42A0DC47400A5DB65 /* ARTWebSocketFactory.h */; settings = {ATTRIBUTES = (Private, ); }; };
 		21E1C0E72A0DC47400A5DB65 /* ARTWebSocketFactory.h in Headers */ = {isa = PBXBuildFile; fileRef = 21E1C0E42A0DC47400A5DB65 /* ARTWebSocketFactory.h */; settings = {ATTRIBUTES = (Private, ); }; };
@@ -1377,6 +1380,7 @@
 		21AC0CC92D4AA0F50030BD23 /* ARTWrapperSDKProxyRealtimeChannels+Private.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; name = "ARTWrapperSDKProxyRealtimeChannels+Private.h"; path = "PrivateHeaders/Ably/ARTWrapperSDKProxyRealtimeChannels+Private.h"; sourceTree = "<group>"; };
 		21AC0CD02D4AA3200030BD23 /* ARTWrapperSDKProxyRealtimeChannel.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = ARTWrapperSDKProxyRealtimeChannel.m; sourceTree = "<group>"; };
 		21AC0CD12D4AA3200030BD23 /* ARTWrapperSDKProxyRealtimeChannels.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = ARTWrapperSDKProxyRealtimeChannels.m; sourceTree = "<group>"; };
+		21BFC2D52D67C58800C05E8B /* ARTRealtimeChannel+Plugins.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; name = "ARTRealtimeChannel+Plugins.h"; path = "PrivateHeaders/Ably/ARTRealtimeChannel+Plugins.h"; sourceTree = "<group>"; };
 		21DCDA8229F818630073A211 /* Ably-iOS.xctestplan */ = {isa = PBXFileReference; lastKnownFileType = text; name = "Ably-iOS.xctestplan"; path = "Test/Ably-iOS.xctestplan"; sourceTree = SOURCE_ROOT; };
 		21DCDA8329F81B350073A211 /* Ably-macOS.xctestplan */ = {isa = PBXFileReference; lastKnownFileType = text; path = "Ably-macOS.xctestplan"; sourceTree = "<group>"; };
 		21DCDA8429F81B550073A211 /* Ably-tvOS.xctestplan */ = {isa = PBXFileReference; lastKnownFileType = text; path = "Ably-tvOS.xctestplan"; sourceTree = "<group>"; };
@@ -2124,6 +2128,7 @@
 				211A60DE29D7272000D169C5 /* ARTConnectionStateChangeParams.m */,
 				D746AE3A1BBC5AE1003ECEF8 /* ARTRealtimeChannel.h */,
 				D746AE421BBC5CD0003ECEF8 /* ARTRealtimeChannel+Private.h */,
+				21BFC2D52D67C58800C05E8B /* ARTRealtimeChannel+Plugins.h */,
 				D746AE3B1BBC5AE1003ECEF8 /* ARTRealtimeChannel.m */,
 				211A60FA29D8ABCF00D169C5 /* ARTChannelStateChangeParams.h */,
 				211A60FE29D8ABF100D169C5 /* ARTChannelStateChangeParams.m */,
@@ -2547,6 +2552,7 @@
 				D746AE1E1BBB5207003ECEF8 /* ARTDataQuery+Private.h in Headers */,
 				2132C2BD29D482E8000C4355 /* ARTClientOptions+TestConfiguration.h in Headers */,
 				D7AE18C91E5B40C900478D82 /* ARTPushAdmin.h in Headers */,
+				21BFC2D72D67C58800C05E8B /* ARTRealtimeChannel+Plugins.h in Headers */,
 				EB1B53FD22F8D91C006A59AC /* ARTQueuedDealloc.h in Headers */,
 				D77394031C6F6FFE00F5478F /* ARTProtocolMessage+Private.h in Headers */,
 				D746AE2F1BBBE7D7003ECEF8 /* ARTPaginatedResult+Private.h in Headers */,
@@ -2682,6 +2688,7 @@
 				D710D69221949EFF008F54AD /* ARTJsonEncoder.h in Headers */,
 				21113B4629DB484200652C86 /* ARTChannel+Subclass.h in Headers */,
 				D710D5B921949D4F008F54AD /* ARTTokenParams+Private.h in Headers */,
+				21BFC2D82D67C58800C05E8B /* ARTRealtimeChannel+Plugins.h in Headers */,
 				D710D51821949C42008F54AD /* ARTPushChannelSubscription.h in Headers */,
 				D710D4B421949B47008F54AD /* ARTAuth+Private.h in Headers */,
 				D710D4C221949B9C008F54AD /* ARTRealtimeTransport.h in Headers */,
@@ -2877,6 +2884,7 @@
 				D710D61621949DDC008F54AD /* ARTHttp.h in Headers */,
 				21113B4729DB484200652C86 /* ARTChannel+Subclass.h in Headers */,
 				D710D69D21949F00008F54AD /* ARTMsgPackEncoder.h in Headers */,
+				21BFC2D62D67C58800C05E8B /* ARTRealtimeChannel+Plugins.h in Headers */,
 				D710D69C21949F00008F54AD /* ARTJsonEncoder.h in Headers */,
 				D710D5C921949D50008F54AD /* ARTTokenParams+Private.h in Headers */,
 				D710D52A21949C44008F54AD /* ARTPushChannelSubscription.h in Headers */,
@@ -4152,7 +4160,10 @@
 				DEFINES_MODULE = YES;
 				DEVELOPMENT_TEAM = "";
 				DYLIB_INSTALL_NAME_BASE = "@rpath";
-				HEADER_SEARCH_PATHS = "$(PROJECT_DIR)/Source/Private";
+				HEADER_SEARCH_PATHS = (
+					"$(PROJECT_DIR)/Source/Private",
+					"$(PROJECT_DIR)/AblyPlugin/include",
+				);
 				INFOPLIST_FILE = "Source/Info-iOS.plist";
 				IPHONEOS_DEPLOYMENT_TARGET = 10.0;
 				LD_RUNPATH_SEARCH_PATHS = (
@@ -4179,7 +4190,10 @@
 				DEFINES_MODULE = YES;
 				DEVELOPMENT_TEAM = "";
 				DYLIB_INSTALL_NAME_BASE = "@rpath";
-				HEADER_SEARCH_PATHS = "$(PROJECT_DIR)/Source/Private";
+				HEADER_SEARCH_PATHS = (
+					"$(PROJECT_DIR)/Source/Private",
+					"$(PROJECT_DIR)/AblyPlugin/include",
+				);
 				INFOPLIST_FILE = "Source/Info-iOS.plist";
 				IPHONEOS_DEPLOYMENT_TARGET = 10.0;
 				LD_RUNPATH_SEARCH_PATHS = (
@@ -4352,7 +4366,10 @@
 				DYLIB_INSTALL_NAME_BASE = "@rpath";
 				FRAMEWORK_VERSION = A;
 				GCC_C_LANGUAGE_STANDARD = gnu11;
-				HEADER_SEARCH_PATHS = "$(SRCROOT)/include";
+				HEADER_SEARCH_PATHS = (
+					"$(SRCROOT)/include",
+					"$(PROJECT_DIR)/AblyPlugin/include",
+				);
 				INFOPLIST_FILE = "Source/Info-macOS.plist";
 				INSTALL_PATH = "$(LOCAL_LIBRARY_DIR)/Frameworks";
 				LD_RUNPATH_SEARCH_PATHS = (
@@ -4392,7 +4409,10 @@
 				DYLIB_INSTALL_NAME_BASE = "@rpath";
 				FRAMEWORK_VERSION = A;
 				GCC_C_LANGUAGE_STANDARD = gnu11;
-				HEADER_SEARCH_PATHS = "$(SRCROOT)/include";
+				HEADER_SEARCH_PATHS = (
+					"$(SRCROOT)/include",
+					"$(PROJECT_DIR)/AblyPlugin/include",
+				);
 				INFOPLIST_FILE = "Source/Info-macOS.plist";
 				INSTALL_PATH = "$(LOCAL_LIBRARY_DIR)/Frameworks";
 				LD_RUNPATH_SEARCH_PATHS = (
@@ -4427,7 +4447,10 @@
 				DEFINES_MODULE = YES;
 				DYLIB_INSTALL_NAME_BASE = "@rpath";
 				GCC_C_LANGUAGE_STANDARD = gnu11;
-				HEADER_SEARCH_PATHS = "$(SRCROOT)/include";
+				HEADER_SEARCH_PATHS = (
+					"$(SRCROOT)/include",
+					"$(PROJECT_DIR)/AblyPlugin/include",
+				);
 				INFOPLIST_FILE = "Source/Info-tvOS.plist";
 				INSTALL_PATH = "$(LOCAL_LIBRARY_DIR)/Frameworks";
 				LD_RUNPATH_SEARCH_PATHS = (
@@ -4466,7 +4489,10 @@
 				DEFINES_MODULE = YES;
 				DYLIB_INSTALL_NAME_BASE = "@rpath";
 				GCC_C_LANGUAGE_STANDARD = gnu11;
-				HEADER_SEARCH_PATHS = "$(SRCROOT)/include";
+				HEADER_SEARCH_PATHS = (
+					"$(SRCROOT)/include",
+					"$(PROJECT_DIR)/AblyPlugin/include",
+				);
 				INFOPLIST_FILE = "Source/Info-tvOS.plist";
 				INSTALL_PATH = "$(LOCAL_LIBRARY_DIR)/Frameworks";
 				LD_RUNPATH_SEARCH_PATHS = (

diff --git a/AblyPlugin/APPluginAPI.m b/AblyPlugin/APPluginAPI.m
@@ -0,0 +1,22 @@
+#import "APPluginAPI.h"
+#import "ARTRealtimeChannel+Plugins.h"
+
+@implementation APPluginAPI
+
++ (void)setPluginDataValue:(nonnull id)value
+                    forKey:(nonnull NSString *)key
+                   channel:(nonnull ARTRealtimeChannel *)channel {
+    [channel setPluginDataValue:value forKey:key];
+}
+
++ (nullable id)pluginDataValueForKey:(nonnull NSString *)key
+                             channel:(nonnull ARTRealtimeChannel *)channel {
+    return [channel pluginDataValueForKey:key];
+}
+
++ (void)addPluginProtocolMessageListener:(APProtocolMessageListener)listener
+                                 channel:(nonnull ARTRealtimeChannel *)channel {
+    [channel addPluginProtocolMessageListener:listener];
+}
+
+@end
diff --git a/AblyPlugin/include/APLiveObjectsPlugin.h b/AblyPlugin/include/APLiveObjectsPlugin.h
@@ -0,0 +1,24 @@
+#import <Foundation/Foundation.h>
+
+@class ARTRealtimeChannel;
+@protocol APLiveObjectsPluginProtocol;
+
+NS_ASSUME_NONNULL_BEGIN
+
+// The `AblyLiveObjects.Plugin` class will _informally_ conform to this (informally so that we don't have to expose this protocol publicly); we keep this protocol simple because there will be no compiler checking
+NS_SWIFT_NAME(LiveObjectsPluginFactoryProtocol)
+@protocol APLiveObjectsPluginFactoryProtocol <NSObject>
+
++ (id<APLiveObjectsPluginProtocol>)createPlugin;
+
+@end
+
+// An internal class of `AblyLiveObjects` will conform to this; this protocol can be complex because compiler will check conformance
+NS_SWIFT_NAME(LiveObjectsPluginProtocol)
+@protocol APLiveObjectsPluginProtocol <NSObject>
+
+- (void)prepareChannel:(ARTRealtimeChannel *)channel;
+
+@end
+
+NS_ASSUME_NONNULL_END
diff --git a/AblyPlugin/include/APPluginAPI.h b/AblyPlugin/include/APPluginAPI.h
@@ -0,0 +1,27 @@
+@import Foundation;
+
+@class ARTRealtimeChannel;
+@class ARTProtocolMessage;
+
+NS_ASSUME_NONNULL_BEGIN
+
+NS_SWIFT_NAME(ProtocolMessageListener)
+typedef void (^APProtocolMessageListener)(ARTProtocolMessage *);
+
+NS_SWIFT_NAME(PluginAPI)
+@interface APPluginAPI: NSObject
+
++ (void)setPluginDataValue:(id)value
+                    forKey:(NSString *)key
+                   channel:(ARTRealtimeChannel *)channel;
+
++ (nullable id)pluginDataValueForKey:(NSString *)key
+                             channel:(ARTRealtimeChannel *)channel;
+
+// Listener will be called each time a protocol message is received
++ (void)addPluginProtocolMessageListener:(APProtocolMessageListener)listener
+                                 channel:(ARTRealtimeChannel *)channel;
+
+@end
+
+NS_ASSUME_NONNULL_END
diff --git a/AblyPlugin/include/ARTProtocolMessage.h b/AblyPlugin/include/ARTProtocolMessage.h
@@ -0,0 +1 @@
+../../Source/PrivateHeaders/Ably/ARTProtocolMessage.h
diff --git a/Package.swift b/Package.swift
@@ -14,6 +14,10 @@ let package = Package(
             name: "Ably",
             targets: ["Ably"]
         ),
+        .library(
+            name: "AblyPlugin",
+            targets: ["AblyPlugin"]
+        ),
     ],
     dependencies: [
         .package(name: "msgpack", url: "/~https://github.com/rvi/msgpack-objective-C", from: "0.4.0"),
@@ -46,6 +50,17 @@ let package = Package(
                 .headerSearchPath("SocketRocket/Internal/RunLoop"),
                 .headerSearchPath("SocketRocket/Internal/Delegate"),
                 .headerSearchPath("SocketRocket/Internal/IOConsumer"),
+                .headerSearchPath("../AblyPlugin/include"),
+            ]
+        ),
+        .target(
+            name: "AblyPlugin",
+            dependencies: [
+                .byName(name: "Ably")
+            ],
+            path: "AblyPlugin",
+            cSettings: [
+                .headerSearchPath("../Source/PrivateHeaders/Ably")
             ]
         )
     ]

diff --git a/Source/ARTClientOptions.m b/Source/ARTClientOptions.m
@@ -10,6 +10,8 @@
 #import "ARTNSString+ARTUtil.h"
 #import "ARTTestClientOptions.h"
 
+const ARTPluginName ARTPluginNameLiveObjects = @"LiveObjects";
+
 NSString *ARTDefaultEnvironment = nil;
 
 @interface ARTClientOptions ()
@@ -140,6 +142,7 @@ - (id)copyWithZone:(NSZone *)zone {
     options.transportParams = self.transportParams;
     options.agents = self.agents;
     options.testOptions = self.testOptions;
+    options.plugins = self.plugins;
 
     return options;
 }

diff --git a/Source/ARTRealtimeChannel.m b/Source/ARTRealtimeChannel.m
@@ -1,4 +1,5 @@
 #import "ARTRealtimeChannel+Private.h"
+#import "ARTRealtimeChannel+Plugins.h"
 #import "ARTChannel+Private.h"
 #import "ARTChannel+Subclass.h"
 #import "ARTDataQuery+Private.h"
@@ -35,6 +36,13 @@
 #if TARGET_OS_IPHONE
 #import "ARTPushChannel+Private.h"
 #endif
+#import "APLiveObjectsPlugin.h"
+
+@interface ARTRealtimeChannel ()
+
+@property (nonatomic, readonly) NSMutableDictionary<NSString *, id> *pluginData;
+
+@end
 
 @implementation ARTRealtimeChannel {
     ARTQueuedDealloc *_dealloc;
@@ -57,10 +65,29 @@ - (instancetype)initWithInternal:(ARTRealtimeChannelInternal *)internal queuedDe
     if (self) {
         _internal = internal;
         _dealloc = dealloc;
+        _pluginData = [[NSMutableDictionary alloc] init];
+
+        if (internal.realtime.options.plugins[ARTPluginNameLiveObjects]) {
+            Class<APLiveObjectsPluginFactoryProtocol> liveObjectsFactoryClass = internal.realtime.options.plugins[ARTPluginNameLiveObjects];
+            id<APLiveObjectsPluginProtocol> liveObjectsPlugin = [liveObjectsFactoryClass createPlugin];
+            [liveObjectsPlugin prepareChannel:self];
+        }
     }
     return self;
 }
 
+- (void)setPluginDataValue:(id)value forKey:(NSString *)key {
+    [self.pluginData setValue:value forKey:key];
+}
+
+- (id)pluginDataValueForKey:(NSString *)key {
+    return self.pluginData[key];
+}
+
+- (void)addPluginProtocolMessageListener:(ARTProtocolMessageListener)listener {
+    [self.internal addPluginProtocolMessageListener:listener];
+}
+
 - (NSString *)name {
     return _internal.name;
 }
@@ -243,6 +270,7 @@ @interface ARTRealtimeChannelInternal () {
 @interface ARTRealtimeChannelInternal ()
 
 @property (nonatomic, readonly) ARTAttachRetryState *attachRetryState;
+@property (nonatomic, readonly) NSMutableArray<ARTProtocolMessageListener> *pluginProtocolMessageListeners;
 
 @end
 
@@ -274,10 +302,15 @@ - (instancetype)initWithRealtime:(ARTRealtimeInternal *)realtime andName:(NSStri
         _attachRetryState = [[ARTAttachRetryState alloc] initWithRetryDelayCalculator:attachRetryDelayCalculator
                                                                                logger:logger
                                                                      logMessagePrefix:[NSString stringWithFormat:@"RT: %p C:%p ", _realtime, self]];
+        _pluginProtocolMessageListeners = [[NSMutableArray alloc] init];
     }
     return self;
 }
 
+- (void)addPluginProtocolMessageListener:(ARTProtocolMessageListener)listener {
+    [self.pluginProtocolMessageListeners addObject:listener];
+}
+
 - (ARTRealtimeChannelState)state {
     __block ARTRealtimeChannelState ret;
 dispatch_sync(_queue, ^{
@@ -628,6 +661,10 @@ - (void)onChannelMessage:(ARTProtocolMessage *)message {
             ARTLogWarn(self.logger, @"R:%p C:%p (%@) unknown ARTProtocolMessage action: %tu", _realtime, self, self.name, message.action);
             break;
     }
+
+    for (ARTProtocolMessageListener listener in self.pluginProtocolMessageListeners) {
+        listener(message);
+    }
 }
 
 - (void)setAttached:(ARTProtocolMessage *)message {

diff --git a/Source/Ably.modulemap b/Source/Ably.modulemap
@@ -130,5 +130,6 @@ framework module Ably {
         header "ARTPendingMessage.h"
         header "ARTEncoder.h"
         header "ARTDeviceStorage.h"
+        header "ARTRealtimeChannel+Plugins.h"
     }
 }
diff --git a/Source/PrivateHeaders/Ably/ARTRealtimeChannel+Plugins.h b/Source/PrivateHeaders/Ably/ARTRealtimeChannel+Plugins.h
@@ -0,0 +1,16 @@
+#import <Ably/ARTRealtimeChannel.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+typedef void (^ARTProtocolMessageListener)(ARTProtocolMessage *);
+
+@interface ARTRealtimeChannel ()
+
+- (void)setPluginDataValue:(id)value forKey:(NSString *)key;
+- (nullable id)pluginDataValueForKey:(NSString *)key;
+
+- (void)addPluginProtocolMessageListener:(ARTProtocolMessageListener)listener;
+
+@end
+
+NS_ASSUME_NONNULL_END
diff --git a/Source/PrivateHeaders/Ably/ARTRealtimeChannel+Private.h b/Source/PrivateHeaders/Ably/ARTRealtimeChannel+Private.h
@@ -10,6 +10,7 @@
 #import <Ably/ARTRealtime+Private.h>
 #import <Ably/ARTQueuedDealloc.h>
 #import <Ably/ARTPushChannel+Private.h>
+#import <Ably/ARTRealtimeChannel+Plugins.h>
 
 @class ARTProtocolMessage;
 @class ARTRealtimePresenceInternal;
@@ -92,6 +93,8 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (void)setOptions:(ARTRealtimeChannelOptions *_Nullable)options callback:(nullable ARTCallback)callback;
 
+- (void)addPluginProtocolMessageListener:(ARTProtocolMessageListener)listener;
+
 #pragma mark ARTEventEmitter
 
 ART_EMBED_INTERFACE_EVENT_EMITTER(ARTChannelEvent, ARTChannelStateChange *)
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		../../Source/PrivateHeaders/Ably/ARTProtocolMessage.h