Reject new lock requests immediately when 1000 goroutines are queued
for the local lock mutex.
We do not reject unlocking, refreshing, or maintenance; they add to the count.
The limit is set to allow for bursty behavior but prevent requests from
overloading the server completely.
Object names of directory objects qualified for ExpiredObjectAllVersions
must be encoded appropriately before calling on deletePrefix on their
erasure set.
e.g., a directory object and regular objects with overlapping prefixes
could lead to the expiration of regular objects, which is not the
intention of ILM.
```
bucket/dir/ ---> directory object
bucket/dir/obj-1
```
When `bucket/dir/` qualifies for expiration, the current implementation would
remove regular objects under the prefix `bucket/dir/`, in this case,
`bucket/dir/obj-1`.
