function isMessageMetadataHeaderimport { isMessageMetadataHeader } from "https://deno.land/x/http_utils@1.0.0/header.ts"; isMessageMetadataHeader(input: string): input is `${MessageMetadataHeader}`Whether the input is MessageMetadataHeader or not. ExamplesExample 1 import { isMessageMetadataHeader } from "https://deno.land/x/http_utils@$VERSION/header.ts"; import { assert } from "https://deno.land/std@$VERSION/testing/asserts.ts"; assert(isMessageMetadataHeader("date")); assert(!isMessageMetadataHeader("<others>")); Parametersinput: stringReturnsinput is `${MessageMetadataHeader}`