Make an iterator-like pattern with overrides or reusing

I am trying to make a iterator like pattern (or builder pattern might be more accurate). Where I want to have a core function which will pass in bytes through the rest of the chain, and each part of the chain would decode it into a specific struct, using a structs decode function, I want it so I can override a part of this chain in a way that makes sense, something like, at compile time it detects if a generic associated with a part of a chain matches with a generic associated with some later p...