code: @Override
      public int size() {
          try {
              lockAllSegments();
              int size = 0;
              for (LinkedHashMapSegment<K, V> seg : segments) {
                  size += seg.size();
              }
              return size;
          } finally {
              unlockAllSegments();
          }
      }
docs: Gets the entry's total number.
  
  @return entry's number