Updates the HSTREAM and HMUSIC channel playback buffers.
|length||The amount of data to render, in milliseconds.
If successful, TRUE is returned, else FALSE is returned. Use BASS_ErrorGetCode
to get the error code.
|BASS_ERROR_NOTAVAIL||Updating is already in progress.
When automatic updating is disabled, this function or BASS_ChannelUpdate
needs to be used to keep the playback buffers updated. The length
parameter should include some safety margin, in case the next update cycle gets delayed. For example, if calling this function every 100ms, 200 would be a reasonable length