cache rewrite

[HopeBaron]

This PR is to:

• Implement indexing for cache items in kord
• Reflection-free implementation
• Introduce a obverver-like relationship on discards instead of descriptions

[lukellmann]

could you provide some examples how you think this all should be used (maybe also compared to the old cache api)? that way it will be easier to review because i would know what i'm looking at and what the intention was.

[HopeBaron]

@Lukellmann https://gist.github.com/HopeBaron/8417dbbbfa814be381b8c8498f4ba534 Above is a full example output:

{SnowflakeSetIndex(snowflakes=[1, 123])=MemberData(guildId=1, userId=123)}
{SnowflakeSetIndex(snowflakes=[123])=UserData(userId=123)}
{}
{}

[lukellmann]

what i just realized is a problem with Cache.filter and Cache.firstOrNull: these will always have O(n) complexity because all objects have to be accessed to be filtered.

[HopeBaron]

Yeah but the implementation doesn't specify a Key no more if you are looking for something you can identify you can easily add that sort of data to your key. Create a key out of it, and get it.