BackgroundListener$checkAppInBackground scheduled N times

[pyricau]

Was just looking at a random Espresso report and noticed this:

Looper (main, tid 1) {5edfd65}
  Message 0: ...
  Message 1: { when=+1s743ms callback=leakcanary.internal.BackgroundListener$checkAppInBackground$1 target=android.os.Handler }
  Message 2: { when=+2s807ms callback=leakcanary.internal.BackgroundListener$checkAppInBackground$1 target=android.os.Handler }
  Message 3: { when=+2s807ms callback=leakcanary.internal.BackgroundListener$checkAppInBackground$1 target=android.os.Handler }
  Message 4: { when=+2s807ms callback=leakcanary.internal.BackgroundListener$checkAppInBackground$1 target=android.os.Handler }
  Message 5: { when=+2s807ms callback=leakcanary.internal.BackgroundListener$checkAppInBackground$1 target=android.os.Handler }
  Message 6: { when=+3s742ms callback=leakcanary.internal.BackgroundListener$checkAppInBackground$1 target=android.os.Handler }
  Message 7: { when=+3s742ms callback=leakcanary.internal.BackgroundListener$checkAppInBackground$1 target=android.os.Handler }
  Message 8: { when=+3s742ms callback=leakcanary.internal.BackgroundListener$checkAppInBackground$1 target=android.os.Handler }
  Message 9: { when=+3s743ms callback=leakcanary.internal.BackgroundListener$checkAppInBackground$1 target=android.os.Handler }
  Message 10: { when=+4s718ms callback=leakcanary.internal.BackgroundListener$checkAppInBackground$1 target=android.os.Handler }
  Message 11: { when=+4s847ms callback=leakcanary.internal.BackgroundListener$checkAppInBackground$1 target=android.os.Handler }
  Message 12: { when=+4s847ms callback=leakcanary.internal.BackgroundListener$checkAppInBackground$1 target=android.os.Handler }
  Message 13: { when=+4s847ms callback=leakcanary.internal.BackgroundListener$checkAppInBackground$1 target=android.os.Handler }
  Message 14: { when=+4s848ms callback=leakcanary.internal.BackgroundListener$checkAppInBackground$1 target=android.os.Handler }

[pyricau]

Ah, this is most likely a bug on our end when using BackgroundListener, likely creating a new instance for every test.

[pyricau]

Actually, there's most likely a bug in LeakCanary as well

leakcanary/leakcanary-android-release/src/main/java/leakcanary/internal/BackgroundListener.kt

Line 46 in 1d93c74

updateBackgroundState(appInBackgroundNow = false)

=> in uninstall we should make sure to cancel the posted runnable, otherwise every app scope schedules a new set.