docs: public ObjectSinkNode removeLast() {
          if ( this.lastNode == null ) {
              return null;
          }
          final ObjectSinkNode node = this.lastNode;
          this.lastNode = node.getPreviousObjectSinkNode();
          node.setPreviousObjectSinkNode( null );
          if ( this.lastNode != null ) {
              this.lastNode.setNextObjectSinkNode( null );
          } else {
              this.firstNode = this.lastNode;
          }
          this.size--;
          return node;
      }