Reloading playerItem in case of playback stall due to network issue causing limitations for consumers

[yaroslavlvov]

Reloading Item internally is causing limitations for consumers: 1. If playback url has a lifetime I need to get new url and reload with that one 2. Some SDKs are forcing to load stream in a custom way (like Google IMA sdk for ads, etc.)

Proposed solution:

1. Give some timeout for player to resolve stall and continue playback with same player item.
2. Instead of internally reload PlayerItem by creating new asset with same URL, provide a callback to the delegate to decide what to do with that to make sdk consumer responsible for Network issue and unability to recover by itself