class IO::Stream::Generic

def index_of(pattern, offset, limit)
n't want to split on the pattern, so we subtract the size of the pattern.
ffset = pattern.bytesize - 1
ndex = @read_buffer.index(pattern, offset)
 = @read_buffer.bytesize - split_offset
 = 0 if offset < 0
 nil if limit and offset >= limit
 nil unless fill_read_buffer
index