test thread/fork speed; reset msg after release.

lichao

2021-03-26 d17450bd7bc9fd5e98e8e2f00999caffe2e301a6

 src/msg.cpp

@@ -59,7 +59,7 @@

}

int Msg::Release(SharedMemory &shm) const
int Msg::Release(SharedMemory &shm) 
{
    if (IsCounted()) {
        const int n = count_->Dec();
@@ -69,7 +69,9 @@
    }
    // free data
    shm.Dealloc(ptr_);
    ptr_ = 0;
    shm.Delete(count_);
    count_ = 0;
    return 0;
}