#3407 has introduced regression in type inference for withTimeoutOptions function which end up referring to Fn<Args, R> type which was declared in other file https://github.com/ipfs/js-ipfs/pull/3407/files#diff-722621abc3ed4edc6ab202fdf684f1607c261394b95da6b3ec79748711056f20

I think TS has this strange WTF where when it can't figure out when JS file is a module it will treat it as if everything is loaded in the same scope. I think that caused withTimeoutOptions not to report errors but silently fail and infer return function as any.

This change fixes that by removes Fn type all together, as it seemed like unnecessary complexity.

Unfortunately nothing seemed to have caught this regression because we set noImplicitAny to false given that many of our dependencies are untyped.