Should have a size limit for message queue

[yantang-msft]

Consider replacing the Queue with SizedQueue, so the memory consumption can be controlled, like the "BacklogSize" in .Net sdk.
https://github.com/Microsoft/ApplicationInsights-Ruby/blob/develop/lib/application_insights/channel/queue_base.rb#L14

[SergeyKanzhelev]

Would you like to send a PR for this?

[yantang-msft]

I can address this later when I have time.
Need to consider between blocking vs non-blocking push operation, or use the default thread safe non-blocking push vs checking size before push.