code: def _readall(self, file, count):
          
          data = b""
          while len(data) < count:
              d = file.read(count - len(data))
              if not d:
                  raise GeneralProxyError("Connection closed unexpectedly")
              data += d
          return data
docs: Receive EXACTLY the number of bytes requested from the file object.
          Blocks until the required number of bytes have been received.