fix: ensure buffered events are sent in order

Before this commit, an event sent in the "connect" handler could be
sent before the events that were buffered while disconnected.

```js
socket.on("connect", () => {
  socket.emit("bar");
});

socket.emit("foo"); // buffered while disconnected
```

In the example above, the "bar" event was sent first, which is not
correct.

Related: #1458

lib/socket.ts

@@ -384,8 +384,8 @@ export class Socket<
     this.id = id;
     this.connected = true;
     this.disconnected = false;
-    this.emitReserved("connect");
     this.emitBuffered();
+    this.emitReserved("connect");
   }
 
   /**

test/socket.ts

@@ -217,6 +217,26 @@ describe("socket", function () {
     );
   });
 
+  it("should emit events in order", (done) => {
+    const socket = io("/", { autoConnect: false });
+    let i = 0;
+
+    socket.on("connect", () => {
+      socket.emit("echo", "second", () => {
+        expect(++i).to.eql(2);
+
+        socket.disconnect();
+        done();
+      });
+    });
+
+    socket.emit("echo", "first", () => {
+      expect(++i).to.eql(1);
+    });
+
+    socket.connect();
+  });
+
   describe("volatile packets", () => {
     it("should discard a volatile packet when the socket is not connected", (done) => {
       const socket = io({ forceNew: true, autoConnect: false });

test/support/server.js

@@ -42,6 +42,10 @@ server.on("connection", (socket) => {
     socket.emit("hi");
   });
 
+  socket.on("echo", (arg, cb) => {
+    cb(arg);
+  });
+
   // ack tests
   socket.on("ack", () => {
     socket.emit("ack", (a, b) => {