stream_select() causes a buffer synchronization which will
clobber the read buffer of any stream that is marked
seekable.

This behaviour is intended, but under win9x, we cannot
always determine if a stream is a FIFO, and this can cause
data loss if the buffer size specified in
php_stream_read() is ever smaller than the amount of data
read in a single read operation (the excess data is lost
during the next stream_select() call).