message: doc: document ordering
diff: @@ -42,6 +42,8 @@ export class Rpc {
  const {seqNum, name, args, result, exception}: any = msg
  if (seqNum === undefined) return
  if (name !== undefined) {
  + // It's important that we wait on `initPromise` here. Otherwise we may try to invoke
  + // a method before `register` is called.
  return void this.initPromise.then(async () => {
  try {
  const fn = this.methods[name]
  