function createHeadInsertionTransformStreamimport { createHeadInsertionTransformStream } from "https://deno.land/x/ultra@v2.0.0-beta.16/stream.ts"; createHeadInsertionTransformStream(insert: () => Promise<string>): TransformStream<Uint8Array, Uint8Array>Parametersinsert: () => Promise<string>ReturnsTransformStream<Uint8Array, Uint8Array>