// Put the '\r' back on buf and drop it from line.
			// Let the next call to ReadLine check for "\r\n".
			if b.r == 0 {
				// should be unreachable
				panic("bufio: tried to rewind past start of buffer")
			}
			b.r--
			line = line[:len(line)-1]
		}
		return line, true, nil
	}

	if len(line) == 0 {
		if err != nil {
			line = nil
		}
		return
	}