docs: update readme with example

Author: Garrett Moseke

README.md

@@ -15,6 +15,22 @@ This DataSync fork allows for `Next` messages to be handled by the Server with a
 
 The Client implemeneted here now also supports sending `Next` messages to the server via adding an `Observable` object, which will automatically wrap and send `Next` frames as it updates.
 
+### Example
+*The client and the server has already gone through [successful connection initialisation.](https://github.com/enisdenjo/graphql-ws/blob/master/PROTOCOL.md#successful-connection-initialisation)*
+1. *Client* generates a unique ID for the following operation
+2. *Client* dispatches the `Subscribe` message with the generated ID through the `id` field and the requested operation passed through the `payload` field
+*All future communication is linked through this unique ID*
+3. *Server* executes the streaming GraphQL operation
+4. *Server* checks if the generated ID is unique across active streaming subscriptions
+    - If not unique, the server will close the socket with the event `4409: Subscriber for <generated-id> already exists`
+    If unique, continue...
+5. *Server* optionally checks if the operation is valid before starting executing it, e.g. checking permissions
+    - If not valid, the server sends an `Error` message and deems the operation complete.
+    If valid, continue...
+6. *Server* & *Client* dispatch results over time with the `Next` message
+    - *Server* & *Client* handle received `Next` messages with their respectively defined callbacks. All Context is assumed to be the same between the two and is established in step 3 when the subscription is created.
+7. The operation completes as described in [the `graphql-transport-ws` protocol](https://github.com/enisdenjo/graphql-ws/blob/master/PROTOCOL.md#streaming-operation)
+
 ## Usage
 
 To use this package, include it in your `Package.swift` dependencies: