feat: implement clone for DeltaTable struct

[mightyshazam]

Description

This PR adds the derive(Clone) attribute to theDeltaTable struct.

Related Issue(s)

Documentation

[roeap]

@mightyshazam - thanks, I actually have been waiting for this PR 😆.

For a looong time folks wanted DeltaTable to be Cloneable and we have always rejected it since cloning the state used to be potentially ridiculously expensive ... now its practically for free 🥲.

So I am fine to merge this. However, I'd be curious about the use case. Specifically in most situations I would recommend cloning the state itself, as DeltaTable just exposes some higher level functionality on top of it and may not have a valid state yet, which forces you to deal with a lot of Options and/or Results which you avoid by just using the Snapshot.

[mightyshazam]

@mightyshazam - thanks, I actually have been waiting for this PR 😆.

For a looong time folks wanted DeltaTable to be Cloneable and we have always rejected it since cloning the state used to be potentially ridiculously expensive ... now its practically for free 🥲.

So I am fine to merge this. However, I'd be curious about the use case. Specifically in most situations I would recommend cloning the state itself, as DeltaTable just exposes some higher level functionality on top of it and may not have a valid state yet, which forces you to deal with a lot of Options and/or Results which you avoid by just using the Snapshot.

I'm working on dotnet bindings for delta rs, and I wanted to enable SQL querying. That requires passing the struct to the register_table method of the data fusion context. Since I have the table stored in a raw pointer, I can't pass ownership to the context. Instead, I would have to construct a new table.
I saw that cloning is easy and cheap, but it wasn't implemented.