Add overflow mb limit to the client

[norberttech]

Currently there is no limit on how large telemetry client queue can grow. If used in some long running backend processes it can even cause memory overflow that could break the process.

I think we should look for a way to tell client to do auto flush when queue size is greater than 5mb (this value should be configurable).

To reduce resource consumption we can try to calculate each new entry size and then just increase the current size pointer in the client.