stream: add an assert() to an obscure seek case

This affects small seeks backwards while within the buffer. Demuxers
usually avoid this, so it's probably not triggered very often. (Although
demux_mkv.c potentially triggers it often, and it uses stream_peek() to
explicitly guarantee that it can use this code to seek back.) The
condition is complex enough to warrant an assertion.

0 files changed, 0 insertions, 0 deletions