帮助中是这样说这个函数的:The web_concurrent_end function marks the end of a concurrent group and initiates the concurrent execution of all the functions that were registered as concurrent-those between the web_concurrent_start and web_concurrent_end functions. Click Concurrent Functions for a list of functions that may be included within a concurrent group.
Note that the functions included within the concurrent group are not executed immediately. Instead they are registered for concurrent execution. When the concurrent group is closed, all of the functions registered as concurrent are executed together. However the number of steps that can be executed concurrently is limited by the Concurrent Connection entry in the Network tab of the run-time settings.