我写了一个程序，用AES加密文件。加密过程在文件流上完成。

• 加密方式：*

public static async Task EncryptUsingAESAsync(FileStream fileReadStream, FileStream fileWriteStream, byte[] key, byte[] iv)
{
    using(Aes aesAlg = Aes.Create())
    {
        aesAlg.Key = key;
        aesAlg.IV = iv;

        ICryptoTransform encryptor = aesAlg.CreateEncryptor();

        using(CryptoStream cryptoStream = new CryptoStream(fileWriteStream, encryptor, CryptoStreamMode.Write))
        {
            await fileReadStream.CopyToAsync(cryptoStream);
        }
    }
}

• 此方法将被调用 *

public static async Task EncryptFileStreamAsync(string absolutePath, byte[] key, byte[] iv)
{
    using(FileStream fReadStream = new FileStream(absolutePath, FileMode.Open, FileAccess.Read))
    {
        using(FileStream fWriteStream = new FileStream($"{absolutePath}.EWW", FileMode.CreateNew, FileAccess.Write))
        {
            await fWriteStream.WriteAsync(iv, 0, iv.Length);
            await CryptoProvider.EncryptUsingAESAsync(fReadStream, fWriteStream, key, iv);
        }
    }

    File.Delete(absolutePath);
}

我读到.NET中的AES实现实际上使用了Windows加密API。那么，我可以等待这些方法（特别是EncryptUsingAESAsync方法），比如异步IO，还是应该在TaskFactoy.StartNew()中显式调用它，以便在单独的线程上完成？还是有其他方法可以获得多线程的好处？