PubNub memory leak detected

[vzhurintulaco]

The cause of memory leak is public class TelemetryManager : IDisposable.
This class is created by public class Pubnub is case of config.EnableTelemetry == true but will never be disposed.
It can lead to significantly increasing of Number of Active Timers and ultimately lead to memory leak.

Also, non-disposed timers can affect monitor tools (e.g. New Relic) -

My suggestion is:

1. Add IDisposable interface to Pubnub class.
2. Implement Dispose method to clear this.TelemetryManager.