add ReadOnlyMemory<RedisKeyOrValue> and Lease<byte> for Lua and Execute

[pairbit]

Tasks:

• add ReadOnlyMemory<RedisKeyOrValue> API for Lua
• add Lease<byte>? API for Lua
• add ScriptEvaluateReadOnlyAsync again if the script does not exist.
• add rent args for key-prefix path
• add ReadOnlyMemory<RedisKeyOrValue> API for Execute
• add Lease<byte>? API for Execute
• add IScriptRequestDisposer to Execute (to return memory to pools, including for fire-and-forget mode)

Links
#2346
#2843
#2844

Please consider this PR, this issue has been raised for a long time

[mgravell]

There's a couple of reasons I've been deferring on this for a little bit...

If we're thinking "efficiency", there's the problem of the return value, and managing it in a way that is flexible and efficient.

I'm not quite ready to release it on the world yet, but a large part of the IO rewrite is "yet to come", and explicitly targets flexible read / write custom command scenarios, including Lua (but also any ad-hoc commands). I'm torn between compromising on an eval[sha] now, bs giving you the real thing "soon" - trust me, it'll be much easier than this.

Thoughts?

[pairbit]

I understand that you want to give the maximum. But the perfect is the enemy of the good. The solution I propose will completely satisfy many and will be a compromise. For most tasks, the current solution will be sufficient. But I understand it's not perfect.

I'd really appreciate your consideration of my merge request. It's a good temporary compromise.