This is something I'm hoping will change with the introduction of Generics. Right now using any custom data structures like immutable map or lists are very cumbersome requiring either code generation or runtime type coercion via `interface{}`.

Go espouses "Share by communicating, don't communicate by sharing" i.e. don't let goroutines communicate by mutating shared data, but then doesn't provide any effective immutable data structures to make this easy.

Being able to safely send pointers to immutable maps over channels would make go very nice to work with. Although I'll never use Go outside of work until they remove nullable pointers which seems unlikely.