squash: update guide with more examples

Signed-off-by: Lucas Holmquist <[email protected]>

Author: lholmquist

API_TRANSITION_GUIDE.md

@@ -28,8 +28,6 @@ app.post("/", (req, res) => {
 
 #### Emitter
 
-The `Emitter` class has been changed with the removal of `Emitter.send()` and the addition of `Emitter.emit()`. This change puts the responsibility for network transport on the developer. See the example below.
-
 `Emit.send` should be transitioned to `HTTP.binary` for binary events and `HTTP.structured` for structured events
 
 `Emit.send` would use axios to emit the events.  Since this now longer available, you are free to choose your own transport protocol.
@@ -73,3 +71,32 @@ function sendWithAxios(message) {
 const emit = emitterFor(sendWithAxios, { mode: Mode.BINARY });
 emit(new CloudEvent({ type, source, data }));
 ```
+
+You may also use the `Emitter` singleton
+
+```js
+const axios = require("axios").default;
+const { emitterFor, Mode, CloudEvent, Emitter } = require("cloudevents");
+
+function sendWithAxios(message) {
+  // Do what you need with the message headers
+  // and body in this function, then send the
+  // event
+  axios({
+    method: "post",
+    url: "...",
+    data: message.body,
+    headers: message.headers,
+  });
+}
+
+const emit = emitterFor(sendWithAxios, { mode: Mode.BINARY });
+// Set the emit
+Emitter.on("cloudevent", emit);
+
+...
+// In any part of the code will send the event
+new CloudEvent({ type, source, data }).emit();
+
+// You can also have several listener to send the event to several endpoint
+```