Adding .ConfigureAwait(false) to your async call takes away the overhead of context switching of threads.
DoSomething(); // on thread 1
await DoMoreAsync().ConfigureAwait(false); // on thread 2
DoSomethingElse(); // continues the work on thread 2 (instead of having to switch to thread 1)
The default for ConfigureAwait is true. But ConfigureAwait(false) is the right thing to do, if the code following the async all does not rely on the context of thread 1 (thread storage of thread 1, for example).