The maximum number of redirector processes to spawn. If you limit
	it too few Squid will have to wait for them to process a backlog of
	URLs, slowing it down. If you allow too many they will use RAM
	and other system resources noticably.
	
	The startup= and idle= options allow some measure of skew in your
	tuning.
	
		startup=
	
	Sets a minimum of how many processes are to be spawned when Squid
	starts or reconfigures. When set to zero the first request will
	cause spawning of the first child process to handle it.
	
	Starting too few will cause an initial slowdown in traffic as Squid
	attempts to simultaneously spawn enough processes to cope.
	
		idle=
	
	Sets a minimum of how many processes Squid is to try and keep available
	at all times. When traffic begins to rise above what the existing
	processes can handle this many more will be spawned up to the maximum
	configured. A minimum setting of 1 is required.

		concurrency=

	The number of requests each redirector helper can handle in
	parallel. Defaults to 0 which indicates the redirector
	is a old-style single threaded redirector.

	When this directive is set to a value >= 1 then the protocol
	used to communicate with the helper is modified to include
	a request ID in front of the request/response. The request
	ID from the request must be echoed back with the response
	to that request.