docs: def _send_ffd(self, pid, aplx_data, address):
          """Send flood-fill data packets."""
          block = 0
          pos = 0
          aplx_size = len(aplx_data)
  
          while pos < aplx_size:
              # Get the next block of data, send and progress the block
              # counter and the address
              data = aplx_data[pos:pos + self.scp_data_length]
              data_size = len(data)
              size = data_size // 4 - 1
  
              arg1 = (NNConstants.forward << 24 | NNConstants.retry << 16 | pid)
              arg2 = (block << 16) | (size << 8)
              self._send_scp(255, 255, 0, SCPCommands.flood_fill_data,
                             arg1, arg2, address, data)
  
              # Increment the address and the block counter
              block += 1
              address += data_size
              pos += data_size