Fix async support

src/OpenSearch/HttpTransport.php

@@ -36,7 +36,7 @@ public function sendRequest(
         array $params = [],
         mixed $body = null,
         array $headers = [],
-    ): array|string|null {
+    ): iterable|string|null {
         $request = $this->createRequest($method, $uri, $params, $body, $headers);
         $response = $this->client->sendRequest($request);
         $statusCode = $response->getStatusCode();

src/OpenSearch/LegacyTransportWrapper.php

@@ -1,8 +1,8 @@
 <?php
 
-namespace OpenSearch;
+declare(strict_types=1);
 
-use GuzzleHttp\Ring\Future\FutureArrayInterface;
+namespace OpenSearch;
 
 // @phpstan-ignore classConstant.deprecatedClass
 @trigger_error(LegacyTransportWrapper::class . ' is deprecated in 2.4.0 and will be removed in 3.0.0.', E_USER_DEPRECATED);
@@ -28,13 +28,11 @@ public function sendRequest(
         array $params = [],
         mixed $body = null,
         array $headers = [],
-    ): array|string|null {
+    ): iterable|string|null {
         $promise = $this->transport->performRequest($method, $uri, $params, $body);
-        $futureArray = $this->transport->resultOrFuture($promise);
-        if ($futureArray instanceof FutureArrayInterface) {
-            return $futureArray->wait();
-        }
-        return $futureArray;
+        // Provide legacy support for options.
+        $options = $headers;
+        return $this->transport->resultOrFuture($promise, $options);
     }
 
 }

src/OpenSearch/TransportInterface.php

@@ -23,6 +23,6 @@ public function sendRequest(
         array $params = [],
         string|array|null $body = null,
         array $headers = [],
-    ): array|string|null;
+    ): iterable|string|null;
 
 }

tests/LegacyTransportWrapperTest.php

@@ -0,0 +1,62 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenSearch\Tests;
+
+use GuzzleHttp\Ring\Future\FutureArray;
+use OpenSearch\ConnectionPool\AbstractConnectionPool;
+use OpenSearch\Connections\Connection;
+use OpenSearch\LegacyTransportWrapper;
+use OpenSearch\Transport;
+use PHPUnit\Framework\MockObject\MockObject;
+use PHPUnit\Framework\TestCase;
+use Psr\Log\LoggerInterface;
+use React\Promise\Deferred;
+
+/**
+ * Tests for the LegacyTransportWrapper class.
+ *
+ * @coversDefaultClass  \OpenSearch\LegacyTransportWrapper
+ * @group legacy
+ * @deprecated in 2.4.2 and will be removed in 3.0.0.
+ */
+class LegacyTransportWrapperTest extends TestCase
+{
+    private Connection&MockObject $connection;
+
+    private AbstractConnectionPool&MockObject $connectionPool;
+
+    private MockObject&LoggerInterface $logger;
+
+    public function setUp(): void
+    {
+        $this->logger = $this->createMock(LoggerInterface::class);
+        $this->connectionPool = $this->createMock(AbstractConnectionPool::class);
+        $this->connection = $this->createMock(Connection::class);
+    }
+
+    public function testSuccess(): void
+    {
+        $deferred = new Deferred();
+        $deferred->resolve(['foo' => 'bar']);
+        $future = new FutureArray($deferred->promise());
+
+        $this->connection->method('performRequest')
+            ->willReturn($future);
+
+        $this->connectionPool->method('nextConnection')
+            ->willReturn($this->connection);
+
+        $transport = new Transport(1, $this->connectionPool, $this->logger);
+
+        $wrapper = new LegacyTransportWrapper($transport);
+
+        $response = $wrapper->sendRequest('GET', 'http://localhost:9200', [], null, []);
+
+        $this->assertIsIterable($response);
+
+        $this->assertEquals(['foo' => 'bar'], $response);
+    }
+
+}