[PopsiclePete]

>io.Reader and Writer are interface{}'s[1].

With this statement, you've shown you have close to 0 Go experience.

* interace{} - a place-holder for a value of "any type". It means "a value that satisfies the empty interface", i.e. an interface with no methods. All types implement it. To do anything with the actual data it encapsulates, you have to do a type assertion to unbox the value. The type assertion will panic or return an error if the type assertion is incorrect. This is something like C's void , or Java's Object.

io.Reader, io.Writer - these are interface types that specify a set of methods that must be implemented by another type in order to satisfy that interface. These are akin to C#/Java's interfaces, but are less restrictive in the sense that any type in Go can implement them, not just "classes". E.g., http.HandlerFunc - a function type that implements the http.Handler interface.