question: private boolean discardUpstreamMediaChunks ( int queueLength ) { if ( mediaChunks . size ( ) <= queueLength ) { return false ; } long totalBytes = 0 ; long startTimeUs = 0 ; long endTimeUs = mediaChunks . getLast ( ) . endTimeUs ; while ( mediaChunks . size ( ) > queueLength ) { MediaChunk removed = mediaChunks . removeLast ( ) ; totalBytes += removed . bytesLoaded ( ) ; startTimeUs = removed . startTimeUs ; removed . release ( ) ; } notifyUpstreamDiscarded ( startTimeUs , endTimeUs , totalBytes ) ; return true ; }
target:  Discard upstream media chunks until the queue length is equal to the length specified.