uninstrumented functions may be called

If application code saves a reference to function when the code is imported, a call to that function won't generate any events in the recording.

For example, with this definition

def free_method():
    return "free method"

def Example:
    static_method = staticmethod(partial(free_method))

Example.static_method()

no events for the call to free_method will be recorded. This is because instrumentation of free_method happens after the module is loaded, and so after the call to partial(free_method)) has saved the reference to free_method.

以 issue 中的 Python 复现程序为起点，然后跟踪相对于由 partial 和 staticmethod 保存的引用，instrumentation 何时被应用。完成的标准是：通过这些已保存引用进行的调用会在记录中生成事件，并且该复现程序由 regression test 覆盖。