Wrap the given async operation to increment the given collector once it is
entered and decrement it once execution is done. This needs a [[gauge]]
collector (since [[counter]] ones cannot be decremented).

Example: Counting the number of in-flight requests in an HTTP server.

Wrap the given async operation to increment the given counters:

- `:total`: incremented when the block is left,
- `:success`: incremented when the block has executed successfully,
- `:failure`: incremented when the block has thrown an exception.

Wrap the given async operation to write its execution time to the given
collector.

Works with [[gauge]], [[histogram]] and [[summary]] collectors.