decode = async rawData => {
  const decoder = new Decoder(rawData)
  const throttleTime = decoder.readInt32()
  const errorCode = decoder.readInt16()
  const members = decoder.readArray(decodeMembers)

  failIfVersionNotSupported(errorCode)

  return { throttleTime: 0, clientSideThrottleTime: throttleTime, errorCode, members }
}
LeaveGroup Response (Version: 3) => throttle_time_ms error_code [members]
  throttle_time_ms => INT32
  error_code => INT16
  members => member_id group_instance_id error_code
    member_id => STRING
    group_instance_id => NULLABLE_STRING
    error_code => INT16