feat(android): initial bitrate

[moskalakamil]

Summary

Added prop to set initial bitrate

Motivation

#3074

Changes

• new prop source.bufferConfig.initialBitrate
• setInitialBitrate in ExoplayerConfig
• new Docs section

Test plan

Run test android app with

<Video
        // ...
        source={{
          // ...
          bufferConfig: {
            // ...
            initialBitrate: {number}
          }
        }}
        reportBandwidth={true}
        onBandwidthUpdate={e => console.log(e.bitrate)}
/>

[freeboub]

Initial bitrate should be a sub property of source (or even better source.bufferConfig).
The issue here under is when you mount the

[KrzysztofMoch]

Yeah I agree - It would be better to move it into source.bufferConfig or ssource

[moskalakamil]

@freeboub Done

[freeboub]

Long time to approve but it looks good to me.

Just a note for you @moskalakamil.
If I remember well this initial bitrate will be apply on player initialization (I implemented similar feature in my past fork).
During your app life cycle, if you just change <Video/> source we don't release and recreate the whole player, then this parameter may not be used. It make sense as if exoplayer already know its expected bandwidth, no need to apply initial bandwidth.

Thank you!