Chapter 6. Thread Usage
When your site accesses a file or an off-box resource such as the database or a web service, the thread executing the request is blocked while it waits for the resource to respond. You now have a thread doing nothing, while there may be requests waiting for a thread to become available.
You can solve this by using asynchronous methods to access files and off-box resources. Instead of blocking a thread, these methods release the thread when they start waiting, so that it can then be used by another request. When the resource becomes available, a new thread is acquired from the thread pool to continue processing.
This chapter shows how to convert synchronous code that blocks the thread to asynchronous code. Each example will ...