import { Buffer } from "https://deno.land/x/oak@v10.6.0/test_deps.ts";
Grows the buffer's capacity, if necessary, to guarantee space for
another n bytes. After .grow(n), at least n bytes can be written to
the buffer without another allocation. If n is negative, .grow() will
throw. If the buffer can't grow it will throw an error.
Based on Go Lang's Buffer.Grow.