Field name use `Arc<str>` instead of `String`

[andrewgazelka]

• cheaper clones
• thought it might make sense since Metadata is already Arc'd but I am not sure.
• not sure this makes sense, please validate

https://github.com/Eventual-Inc/Daft/blob/08ca9a4078e4506afc9b774bd2f073eee94a38d9/src/daft-schema/src/field.rs#L17

[raunakab]

I would support converting over to Arc<str> as well. I believe there was a cool YouTube video referencing why Arc<str>s are more preferable in many situations than just regular Strings.

The most applicable point here is that I believe the actual field names are never in-place mutated. So yes, would make more sense to Arc<str> it.

[raunakab]

Found it: https://www.youtube.com/watch?v=A4cKi7PTJSs.

[samster25]

@andrewgazelka I think this makes sense since we often clone Fields which could cause a redundant memory allocation for String