Check activateFiber failed

I try to use ExecutorLoopController in FiberManager and use CPUThreadPoolExecutor, as shown in the following example:

```cpp
#include
#include
#include

int main() {
auto executor = std::make_shared(3);
auto fm = std::make_shared(
std::make_unique(executor.get()));
for(int i=0;i<10000;i++){
fm->add([](){
int a=1;
int b=1;
for(int j=0;j<100;j++){
a = a+b;
b = a+b;
}
});
}
executor->join();
return 0;
}
```

But after running, the following error is output:

```
F20230222 17:43:26.939141 548510 FiberManagerInternal-inl.h:67] Check failed: activeFiber_ == (Fiber*)nullptr (0 vs. 0)
*** Check failure stack trace: ***
F20230222 17:43:26.939352 548511 FiberManagerInternal-inl.h:67] Check failed: activeFiber_ == (Fiber*)nullptr (0x7f0c13027000 vs. 0)
```

Did I write something wrong? How should I use them correctly?

Start with the supplied reproducer and inspect FiberManagerInternal-inl.h:67, then trace how ExecutorLoopController interacts with CPUThreadPoolExecutor and FiberManager. Determine whether the example violates the expected usage or exposes a library defect; done means establishing the correct behavior and either documenting the usage or providing a focused fix and regression test.

Written by the indexing model from the issue text.