avformat/hlsenc: Only write something if there is something to write

This is especially important in case avio_write() would be switched
to an unsigned type like size_t, then a potential error from avio_read()
(with negative return value) would no longer be handled gracefully by
avio_write().

Reviewed-by: Steven Liu <lq@chinaffmpeg.org>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

0 files changed, 0 insertions, 0 deletions