Closing MetricBuffers after all interval buffers are outside the age threshold.

Closing MetricBuffers after all interval buffers are outside the age threshold.

MetricsBuffers are timers, these timers fire every interval but never die. Every new metric gets a timer that fires every interval. This causes CPU to increase with each new metric even if that metric is sparse. Ultimately leading to 100% CPU usage even when no metrics are being sent.