2.4.0

Features:

• The screen recorder services have been moved to the library (instead of the example)
• Add zoom ratio API support for Android < R
• Introducing a life cycle observer for streamers called StreamerLifeCycleObserver
• Overload camera streamers' startPreview API to take a SurfaceView or a TextureView as input
  parameter
• Add isConnected field in live streamers

Bug fixes:

• Clamp camera range settings: zoom, exposure,...