docs: def _name_value(self, s):
          """Parse a (name,value) tuple from 'name value-length value'."""
          parts = s.split(b' ', 2)
          name = parts[0]
          if len(parts) == 1:
              value = None
          else:
              size = int(parts[1])
              value = parts[2]
              still_to_read = size - len(value)
              if still_to_read > 0:
                  read_bytes = self.read_bytes(still_to_read)
                  value += b'\n' + read_bytes[:still_to_read - 1]
          return (name, value)