code: def _read_http_continuation(self, size, kind, flag):
          
          _flag = dict(
              END_HEADERS=False,      # bit 2
          )
          for index, bit in enumerate(flag):
              if index == 2 and bit:
                  _flag['END_HEADERS'] = True
              elif bit:
                  raise ProtocolError(f'HTTP/2: [Type {kind}] invalid format', quiet=True)
              else:
                  continue
  
          _frag = self._read_fileng(size) or None
  
          data = dict(
              flags=_flag,
              frag=_frag,
          )
  
          return data
docs: Read HTTP/2 WINDOW_UPDATE frames.
  
          Structure of HTTP/2 WINDOW_UPDATE frame [RFC 7540]:
              +-----------------------------------------------+
              |                 Length (24)                   |
              +---------------+---------------+---------------+
              |   Type (8)    |   Flags (8)   |
              +-+-------------+---------------+-------------------------------+
              |R|                 Stream Identifier (31)                      |
              +---------------------------------------------------------------+
              |                   Header Block Fragment (*)                 ...
              +---------------------------------------------------------------+
  
              Octets      Bits        Name                    Description
                0           0     http.length             Length
                3          24     http.type               Type (2)
                4          32     http.flags              Flags
                5          40     -                       Reserved
                5          41     http.sid                Stream Identifier
                9          73     http.frag               Header Block Fragment