…ver. (#2152)

Currently only the first endpoint of the server will initiate a reverse connection, resulting in the possibility to connect only to it. This change enables connection to all the server's endpoints via reverse connect.

Fix a few cases (not all) where TCS are not properly disposed. Specifically BeginConnect, which may cause resource leaks.

…2155)

Cherry pick bugfix from #2146:
ReadExtensionObject returns partial JSON for some types.
It appears that this is due to the JSON being read before the JsonTextWriter is closed.

see also: 2a4ba56

Co-authored-by: Markus Horstmann <markushorstmann@hotmail.com>

#2143)

Currently the session reconnect requires to create and destroy the object and to lock the operation in the client code.
The refactored version is backward compatible but allows for a single instance to handle reconnects during the lifetime of the client. In addition no more locking is necessary in the client code.
- exponential backoff is enabled by using a constructor  `new SessionReconnectHandler( true, 30000);` which would set the maxReconnectPeriod` to 30000ms. The backoff period is doubled after every unsuccessful request.
- a 10% random jitter is added to every timer update.
- The `public virtual int JitteredReconnectPeriod(int reconnectPeriod)` and `public virtual int CheckedReconnectPeriod(int reconnectPeriod, bool exponentialBackoff = false)` can be overloaded to implement custom jitter and backoff implementations.
- A new `ISession.MinPublishRequestCount` property can be set to enforce a minimum number of active publish requests. Default behavior is one publish request per subscription. It can help for low latency high frequency publish intervals.
-  A new `PublishSequenceNumbersToAcknoledge` event is implemented which allows to defer ack of sequence numbers until fully processed by the client.
All new methods/properties ar not breaking changes and by default there is no behavior change, all existing code should work and compile aginst the update flawlessly.
- A bugfix in the reconnect handler, when a server changed the application certificate the reconnect ends up in an endless loop, because the `EndpointDescription` is not updated. The fix updates the endpoint from the server if a `BadSecurityChecksFailed` error os returned and then tries to reconnect with a new session.

…nnect (#2160)

- due to the new `MinPublishRequestCount` property publish requests are being sent after reconnect even if no subscription is active
- Improve sample code to show how to dispose the old session after reconnect