Improve typing around event emitter handlers (#2180)

src/models/event-status.ts

@@ -0,0 +1,40 @@
+/*
+Copyright 2015 - 2022 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+/**
+ * Enum for event statuses.
+ * @readonly
+ * @enum {string}
+ */
+export enum EventStatus {
+    /** The event was not sent and will no longer be retried. */
+    NOT_SENT = "not_sent",
+
+    /** The message is being encrypted */
+    ENCRYPTING = "encrypting",
+
+    /** The event is in the process of being sent. */
+    SENDING = "sending",
+
+    /** The event is in a queue waiting to be sent. */
+    QUEUED = "queued",
+
+    /** The event has been sent to the server, but we have not yet received the echo. */
+    SENT = "sent",
+
+    /** The event was cancelled before it was successfully sent. */
+    CANCELLED = "cancelled",
+}