public static long getHeapAllocationBytes(ByteBuffAllocator... allocators) {
    long heapAllocBytes = 0;
    for (ByteBuffAllocator alloc : Sets.newHashSet(allocators)) {
      heapAllocBytes += alloc.getHeapAllocationBytes();
    }
    return heapAllocBytes;
  }
The {@link ConcurrentLinkedQueue#size()} is O(N) complexity and time-consuming, so DO NOT use
the method except in UT.
hbase-common/src/main/java/org/apache/hadoop/hbase/io/ByteBuffAllocator.java