The function dropdown will contain the available functions to call in your program.
Once you select a function to call, the inputs and outputs for that function will populate in the settings panel. Select your inputs and outputs as you would for any module.
The Run Async setting in the Function Call module allows you to asynchronously call a function that runs an "expensive" or long-running task.
One common use-case for this setting is to immediately return a
200 Success response from the HTTP Response module, while performing a long-running task in the background, on another thread.