class IO::Stream::Generic

def peek(size = nil)
	if size
		until @eof or @read_buffer.bytesize >= size
			# Compute the amount of data we need to read from the underlying stream:
			read_size = size - @read_buffer.bytesize
			
			# Don't read less than @block_size to avoid lots of small reads:
			fill_read_buffer(read_size > @block_size ? read_size : @block_size)
		end
		return @read_buffer[..([size, @read_buffer.size].min - 1)]
	end
	until (block_given? && yield(@read_buffer)) or @eof
		fill_read_buffer
	end
	return @read_buffer
end