Memory leak when systemStats are enabled

[senzzzi]

There's a memory leak when systemStats are set to true. The function "sendFlushStats" puts the system stats metrics in the buffers, the "flush" method is called if the buffers are full and the "sendFlushStats" is called again. Because of that there's a loop every time the buffers are at the "maximum capacity" before sending the metrics.

[miguelcnf]

It looks like this isn't fixed yet. Further investigation required.