在调用立即等待的异步方法时，有多少性能损失？

A lot of API's are moving toward exposing only asynchronous methods. How much of a performance hit is there in scenarios where you have to immediately wait on these methods? Am I wrong in assuming that it causes the current thread to wait on a spawned thread to complete? Or does the CLR perform some sort of magic in these scenarios and make it all execute in the same thread?A lot of API's are moving toward exposing only