static Singleton< ShutdownSocketSet, PrivateTag > singleton
—— Concurrent Priority Queue Implementation ——
static std::shared_ptr< T > try_get()
std::shared_ptr< ShutdownSocketSet > tryGetShutdownSocketSet()
ReadMostlySharedPtr< ShutdownSocketSet > tryGetShutdownSocketSetFast()
static folly::ReadMostlySharedPtr< T > try_get_fast()