code: function string(obj, vonly) {
    var vtype = this.type(0)
      , key = !vonly ? this.getStringBuffer(obj.key) : new Buffer(0)
      , value = this.getStringBuffer(obj.value);
    return Buffer.concat(
      [
        vtype,
        key,
        value
      ],
      vtype.length + key.length + value.length
    )
  }
docs: Get a string key buffer.