Implements suspendWebSocketConnection and resumeWebSocketConnection

[mliao95]

Issue Number:

Description:

What are the changes? Why are we making them?

This PR implements and exposes two new functions, suspendWebSocketConnection and resumeWebSocketConnection. Suspending websocket connections will disconnect the websocket and prevent any further attempts to re-establish a websocket connection. The suspension can only be lifted by calling resumeWebSocketConnection which will immediately re-attempt to re-establish a connection to the active chat session.

These APIs will give customers increased flexibility in managing the websocket connection from their UI.

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Functional backward compatibility:

Does this change introduce backwards incompatible changes? [YES/NO]

NO

Does this change introduce any new dependency? [YES/NO]

NO

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Testing:

Is the code unit tested?

Unit testing will come as fast-follow

Have you tested the changes with a sample UI (e.g. Android Mobile Chat Example)?

Yes

Here are a list of manual test cases to run through:

• Initiating chat and connecting with an agent
• Retrieving transcript
• Disconnecting from chat
• Sending a message to the agent
  • See typing bubbles on agent side
  • See read/delivered receipt on client side
  • Receiving a message from the agent
  • See typing bubbles on client side
  • See read/delivered receipt on agent side
  • Sending an attachment to the agent (try .txt, .pdf, .jpg)
  • Preview the attachment on click
  • Receiving an attachment from the agent
  • Preview the attachment on click
• Close the application (Without ending chat) → open app again → Start chat → Should Retrieve transcript from a previous chat session

[chauhuynh97]

nit: missing 'to' in 'due to'. Same comment for ongoing reconnection case below. This can be fixed with PR for unit tests