export function asUint8Array(input: unknown): Uint8Array | null {
  if (input instanceof Uint8Array) return input;
  if (ArrayBuffer.isView(input)) {
    return new Uint8Array(input.buffer, input.byteOffset, input.byteLength);
  }
  if (input instanceof ArrayBuffer) return new Uint8Array(input);
  return null;
}