presto-main/src/main/java/io/prestosql/execution/resourcegroups/WeightedFairQueue.java/Node/Node
class Node:        private Node(E value, Usage usage, long logicalCreateTime)
        {
            this.value = requireNonNull(value, "value is null");
            this.usage = requireNonNull(usage, "usage is null");
            this.logicalCreateTime = logicalCreateTime;
        }