Add new API like write_opt to allow users to pass an OpWrite directly

[Xuanwo]

Hello, everyone,

While reviewing a PR like this one, I noticed a common pattern where users struggle to work with our write_with API. This API is designed for more advanced Rust users, but it can be quite difficult to use when users try to wrap it.

So, I'm wondering if it would be a good idea to expose OpXxx directly, allowing users to use them more straightforwardly, like this:

let opt = OpWrite::default();
let _ = op.write_opt(path, data, opt).await?;

Following the same pattern, we could introduce read_opt, list_opt, and more.

What do you think?