message: Add 'm.thread' relation for replies to a threaded event
diff: @@ -35,6 +35,8 @@ import Spinner from './Spinner';
  import ReplyTile from "../rooms/ReplyTile";
  import Pill from './Pill';
  import { Room } from 'matrix-js-sdk/src/models/room';
  +import { threadId } from 'worker_threads';
  +import { RelationType } from 'matrix-js-sdk/src/@types/event';
  /**
  * This number is based on the previous behavior - if we have message of height
  @@ -226,13 +228,30 @@ export default class ReplyThread extends React.Component<IProps, IState> {
  public static makeReplyMixIn(ev: MatrixEvent) {
  if (!ev) return {};
  - return {
  +
  + const mixin: any = {
  'm.relates_to': {
  'm.in_reply_to': {
  'event_id': ev.getId(),
  },
  },
  };
  +
  + /**
  + * If the event replied is part of a thread
  + * Add the `m.thread` relation so that clients
  + * that know how to handle that relation will
  + * be able to render them more accurately
  + */
  + if (ev.isThreadRelation) {
  + mixin['m.relates_to'] = {
  + ...mixin['m.relates_to'],
  + rel_type: RelationType.Thread,
  + event_id: ev.threadRootId,
  + };
  + }
  +
  + return mixin;
  }
  public static hasThreadReply(event: MatrixEvent) {
  