src/vs/base/common/ternarySearchTree.ts/TernarySearchTree/_dfsEntries
class TernarySearchTree:	private _dfsEntries(node: TernarySearchTreeNode<K, V> | undefined, bucket: [K, V][]) {
		// DFS
		if (!node) {
			return;
		}
		if (node.left) {
			this._dfsEntries(node.left, bucket);
		}
		if (node.value) {
			bucket.push([node.key!, node.value]);
		}
		if (node.mid) {
			this._dfsEntries(node.mid, bucket);
		}
		if (node.right) {
			this._dfsEntries(node.right, bucket);
		}
	}