This is used to determine which delay pool a request falls into.
delay_access is sorted per pool and the matching starts with pool 1,
then pool 2, ..., and finally pool N. The first delay pool where the
request is allowed is selected for the request. If it does not allow
the request to any pool then the request is not delayed (default).
For example, if you want some_big_clients in delay
pool 1 and lotsa_little_clients in delay pool 2:
delay_access 1 allow some_big_clients
delay_access 1 deny all
delay_access 2 allow lotsa_little_clients
delay_access 2 deny all
delay_access 3 allow authenticated_clients
See also delay_parameters and delay_class.