use tuple style struct in C binding

[asukaminato0721]

Which issue does this PR close?

Closes #5161

Rationale for this change

What changes are included in this PR?

use tuple to avoid inner.

Are there any user-facing changes?

[asukaminato0721]

the change in readme: https://stackoverflow.com/a/21594/13040423

[tisonkun]

Fair enough to move forward in my opinion.

What do you think? @Xuanwo @yuchanns @xyjixyjixyji

[Xuanwo]

It seems like it's just changing from .inner to .0. I'm not sure if it's better to stick with the old style for a more readable and consistent approach when we have more than one field like in opendal_bytes.

Does it make a difference in understanding or performance in a public API on the C side?

[yuchanns]

It seems like it's just changing from .inner to .0. I'm not sure if it's better to stick with the old style for a more readable and consistent approach when we have more than one field like in opendal_bytes.

Does it make a difference in understanding or performance in a public API on the C side?

+1

Does it impact the performance?

[asukaminato0721]

Does it make a difference in understanding or performance in a public API on the C side?

no.

Tuple style is just a syntax sugar that has 0 instead of inner as a field.

[tisonkun]

So we may suspend this request and perhaps review it again before we build the release process for the C binding.

[xyjixyjixyji]

IMO inner name provides better semantics when developers are reading the actual header files.