Optional extra information that may be provided for
; currently only applicable
for deletions which may get queued.
Number of queued deletions (of all types) in deletion queue.
Number of entries in queue allowed, before refusing to add deferred
deletions (and just do straight blocking).
Maximum amount of estimated queue-induced delay we will accept
to try a "deferred" (non-blocking) deletion (which results in 202 response)
Estimated per-operation delay, in milliseconds