def to_s
      extras_s = extras_to_s
      key_s = self[:key].to_s
      value_s = self[:value].to_s
      self[:extras_length] = extras_s.length
      self[:key_length] = key_s.length
      self[:total_body_length] = extras_s.length + key_s.length + value_s.length
      header_to_s + extras_s + key_s + value_s
    end
def to_s
      extras_s = extras_to_s
      key_s = self[:key].to_s
      value_s = self[:value].to_s
      self[:extras_length] = extras_s.length
      self[:key_length] = key_s.length
      self[:total_body_length] = extras_s.length + key_s.length + value_s.length
      header_to_s + extras_s + key_s + value_s
    end
Serialize for wire