Track disconnected issue

[GrapeBaBa]

If qlean is unable to handle the requests then the requests will continue to be added in pending_rpc_requests in sendStatusRequest function. I think we need to have a timeout mechanism here else the PendingRPCMap will grow excessive large and lead to huge memory usuage.

Currently the pending response gets cleared if a response or an error is received but it should be pruned on TTL basis as well I believe.

Cool, will look if it is internally also have a timeout, on the ansible test, the error is timedout. And right now this request only triggered on peer connected may be not a big problem.

And actually I found lantern could handle this rpc but finally we still disconnect with lantern, the root cause probably not found right now, this change works verified on the ansible test by @ch4r10t33r. Create another issue to continue tracking the disconnect issue.

Originally posted by @GrapeBaBa in #438 (comment)