@spec download(
  String.t(),
  keyword()
) :: {:ok, binary()} | {:error, term()}

Download an asset from CloudKit.

Parameters

• download_url: The signed download URL from an asset field
• opts: Download options

@spec upload(String.t(), String.t(), String.t(), keyword()) ::
  {:ok, map()} | {:error, term()}

Upload a file to CloudKit as an asset.

This is a two-step process:

1. Get upload URL from CloudKit
2. Upload the file content to that URL