media/src/main/java/androidx/media/MediaPlayer2Impl.java
private void unregisterPlayerEventCallback(@NonNull PlayerEventCallback cb) {
        if (cb == null) {
            throw new IllegalArgumentException("Illegal null PlayerEventCallback");
        }
        synchronized (mLock) {
            mPlayerEventCallbackMap.remove(cb);
        }
    }
/**
     * Removes a previously registered callback for player events
     * @param cb the callback to remove
     */
Removes a previously registered callback for player events
@param cb the callback to remove
Removes a previously registered callback for player events @param cb the callback to remove
private void unregisterPlayerEventCallback(@NonNull PlayerEventCallback cb) {
        if (cb == null) {
            throw new IllegalArgumentException("Illegal null PlayerEventCallback");
        }
        synchronized (mLock) {
            mPlayerEventCallbackMap.remove(cb);
        }
    }
private void unregisterPlayerEventCallback ( @ NonNull PlayerEventCallback cb ) { if ( cb == null ) { throw new IllegalArgumentException ( "Illegal null PlayerEventCallback" ) ; } synchronized ( mLock ) { mPlayerEventCallbackMap . remove ( cb ) ; } }
Removes a previously registered callback for player events
 @param cb the callback to remove
Removes a previously registered callback for player events @param cb the callback to remove