Not collecting memory if no request arrives

[danielfireman]

It is easy to imagine a metrics collector running on an idle (not receiving requests) server. That consumes memory, which is not going to be collected in the current model. Opening this issue to discuss/implement proposals.

As the go implementation actually switches the GC off (differently from the JVM implementation), we need to worry about this

@thiagomanel any suggestion/comment about this issue?