- retry-request? #!optional predicateparameter
This procedure is invoked when a retry should take place, to determine if it should take place at all. It should be a procedure accepting a request object and returning #f or a true value. If the value is true, the new request will be sent. Otherwise, the error that caused the retry attempt will be re-raised.
Defaults to idempotent?, from intarweb. This is because non-idempotent requests cannot be safely retried when it is unknown whether the previous request reached the server or not.