What does an asynchronous method return in programming?

The OnActionExecution method in the context of HTTP request processing usually refers to ASP.NET Core and is used in action filters.

This method is called before and after the execution of a controller action. It allows executing additional logic, such as logging, permission checks, or modifying the result.

Example of usage:

public class MyActionFilter : IActionFilter
{
    public void OnActionExecuting(ActionExecutingContext context)
    {
        // Logic before action execution
    }

    public void OnActionExecuted(ActionExecutedContext context)
    {
        // Logic after action execution
    }
}

If it is OnActionExecutionAsync, then it is an asynchronous method that takes a delegate for continuing the action execution and allows executing code before and after the action call.

Thus, OnActionExecution is an extension point for injecting additional logic around the execution of controller methods.