参考资料：
http://blogs.msdn.com/b/tess/archive/2008/04/17/how-does-the-gc-work-and-what-are-the-sizes-of-the-different-generations.aspx
https://msdn.microsoft.com/en-us/library/ms973837.aspx
http://content.atalasoft.com/h/i/58205464-basic-memory-housekeeping-net-memory-management-part-1