Implement RTN20C: Handle os connectivity event while CONNECTING

[deanna-lad]

See ably/specification#135 and RTN20c

When CONNECTING, if the operating system indicates that the underlying internet connection is now available, the client should restart the pending connection attempt

As part of this work, we should also ensure that RTN20a and RTN20c are implemented correctly. Also, "Connection: Handle OS connectivity events" should be added to the features.yml file.

[sync-by-unito]

➤ Automation for Jira commented:

The link to the corresponding Jira issue is https://ably.atlassian.net/browse/SDK-3507

[maratal]

https://sdk.ably.com/builds/ably/specification/main/features/#RTN20a

When CONNECTED, CONNECTING or DISCONNECTING, if the operating system indicates that the underlying internet connection is no longer available...

Is DISCONNECTING even a thing?

enum ConnectionState: // RTN4
  INITIALIZED
  CONNECTING
  CONNECTED
  DISCONNECTED
  SUSPENDED
  CLOSING
  CLOSED
  FAILED

@SimonWoolf @owenpearson

[owenpearson]

@maratal yeah DISCONNECTING is not a thing - that should say DISCONNECTED. See ably/specification#146.