message: writer events are unused in favor of notifyBranchUpdate
diff: const Error = require('@cardstack/plugin-utils/error');
  const logger = require('heimdalljs-logger');
  -const EventEmitter = require('events');
  -class Writers extends EventEmitter {
  +class Writers {
  constructor(schemaCache) {
  - super();
  this.schemaCache = schemaCache;
  this.log = logger('writers');
  }
  @@ -20,7 +18,6 @@ class Writers extends EventEmitter {
  if (newSchema) {
  this.schemaCache.notifyBranchUpdate(branch, newSchema);
  }
  - this.emit('changed', { branch, type, id: response.id });
  return response;
  }
  @@ -35,7 +32,6 @@ class Writers extends EventEmitter {
  if (newSchema) {
  this.schemaCache.notifyBranchUpdate(branch, newSchema);
  }
  - this.emit('changed', { branch, type, id });
  return response;
  }
  @@ -50,7 +46,6 @@ class Writers extends EventEmitter {
  if (newSchema) {
  this.schemaCache.notifyBranchUpdate(branch, newSchema);
  }
  - this.emit('changed', { branch, type, id });
  }
  async _finalizeAndReply(pending) {
  