Each time we process a piece deletion on the storagenode, monitor how
long the item was in the queue and the size of the queue.
Change-Id: I23f1a44f8b9cecb901bdf4739d55c005ffed4bef
To improve delete performance, we want to process deletes asynchronously
once the message has been received from the satellite. This change makes
it so that storagenodes will send the delete request to a piece Deleter,
which will process a "best-effort" delete asynchronously and return a
success message to the satellite.
There is a configurable number of max delete workers and a max delete
queue size.
Change-Id: I016b68031f9065a9b09224f161b6783e18cf21e5
