code: def read_var_str(self, max_size=sys.maxsize):
          
          length = self.read_var_int(max_size)
          return self.unpack(str(length) + 's', length)
docs: Similar to `ReadString` but expects a variable length indicator instead of the fixed 1 byte indicator.
  
          Args:
              max_size (int): (Optional) maximum number of bytes to read.
  
          Returns:
              bytes: