import { TreeBuilderBase } from "https://deno.land/x/rimbu@1.2.1/list/custom/builder/tree/tree-builder.ts";
Parameters
child: BlockBuilder<T, C>
x/rimbu/list/custom/builder/tree/tree-builder.ts>TreeBuilderBase#appendMiddle
import { TreeBuilderBase } from "https://deno.land/x/rimbu@1.2.1/list/custom/builder/tree/tree-builder.ts";