void SeekStream(APTR handle, ULONG pos);
HWSNDFLAGS_CANSEEK in
OpenStream(). However, seeking back to position 0 has to be
implemented by all plugins - no matter whether HWSNDFLAGS_CANSEEK has
been set or not. If SeekStream() is called with 0 as the new position, you need
to rewind the stream so that the next call to StreamSamples()
returns PCM frames right from the start of the stream.
Warning: Due to a bug in Hollywood 5.x this function is called with non-zero
positions even if HWSNDFLAGS_CANSEEK has not been set. This has been
fixed in Hollywood 6.0. In Hollywood 6.0 and up SeekStream() is only ever called
with a zero position if HWSNDFLAGS_CANSEEK hasn't been set.
This function must be implemented in a thread-safe way.