We have a struct with about 50 methods, each for an endpoint, that can be categorized because it has methods like send_messagedelete_messageedit_message, so how would you go around doing this with minimum overhead? (The methods are somewhat similar to Client in twilight_http::client - Rust)
Most of the time, when you've got lots of methods like this you'll notice they all follow a similar pattern in a fairly boring way.
If that's the case, you could use code generation to generate the methods and categories from some higher-level spec. That's what the AWS SDK and Google APIs projects do, for example.
This code generation could take the form of Rust code that literally generates the code as a string from some definition file or it could be a macro_rules! macro.
It's really up to you which approach you take, although I prefer to generate source code from a Rust function because it lets you check the generated code into version control and view it. Here is an example from another project where I generate code for some AST stuff and make sure it's in sync with syntax_kind.rs and ast.rs.