Method is_empty

deps/concurrentqueue/concurrentqueue.h:1549–1568

		
		template<InnerQueueContext context>
		inline bool is_empty() const
		{
			MOODYCAMEL_CONSTEXPR_IF (context == explicit_context && BLOCK_SIZE <= EXPLICIT_BLOCK_EMPTY_COUNTER_THRESHOLD) {
				// Check flags
				for (size_t i = 0; i < BLOCK_SIZE; ++i) {
					if (!emptyFlags[i].load(std::memory_order_relaxed)) {
						return false;
					}
				}
				
				// Aha, empty; make sure we have all other memory effects that happened before the empty flags were set
				std::atomic_thread_fence(std::memory_order_acquire);
				return true;
			}
			else {
				// Check counter
				if (elementsCompletelyDequeued.load(std::memory_order_relaxed) == BLOCK_SIZE) {
					std::atomic_thread_fence(std::memory_order_acquire);
					return true;
				}
				assert(elementsCompletelyDequeued.load(std::memory_order_relaxed) <= BLOCK_SIZE);
				return false;
			}