RateLimiter

Name	Type	Default	Description
`custom_log_fields`	object	-	Log fields for custom logging. Inherited by nested blocks.
`key`	string	-	The expression defining which key to be used to identify a visitor.
`per_period`	number	-	Defines the number of allowed requests in a period.
`period`	duration	-	Defines the rate limit period.
`period_window`	string	`"sliding"`	Defines the window of the period. A `fixed` window permits `per_period` requests within `period`. After the `period` has expired, another `per_period` request is permitted. The sliding window ensures that only `per_period` requests are sent in any interval of length `period`.

Name	Description
`error_handler`	Configures an error handler (zero or more).