网址： https://codereview.qt-project.org/#patch,sidebyside,45271,5,src/corelib/kernel/qobject.cpp
https://codereview.qt-project.org/#patch,sidebyside,45271,5,src/corelib/doc/snippets/code/src_corelib_thread_qthread.cpp
https://codereview.qt-project.org/#patch,sidebyside,45271,5,src/corelib/thread/qthread.cpp