code: public int SaveField(ByteArrayWriter writer) {
          writer.writeInt(m_spFieldValue.length);
          writer.writeInt(m_nFieldFlags);
          writer.writeZString(m_spFieldName, "US-ASCII");
          writer.writeBytes(m_spFieldValue);
  
          return GetFieldSize();
      }
docs: output the entire field to a buffer (GetFieldSize() bytes)