We'll introduce storage metrics in SERVER-93991 and store the metrics on the recovery unit. There are cases where the recovery unit is swapped off of the current operation (callers of setRecoveryUnit, releaseRecoveryUnit, and releaseAndReplaceRecoveryUnit) and the metrics could therefore be implicitly reset.

We should evaluate each caller for whether the storage metrics should be copied to the new recovery unit on the operation so that operations have continued access to the metrics.