wormhole: Don't call reflect twice on message

[Jacalz]

Cleans up some code that was doing double reflect calls when only one was necessary,

[psanford]

The go specification does not require an interface implementation to be a pointer type, as long as the method receiver is not a pointer:

package main

import (
	"fmt"
)

type concreteFoo struct {
}

func (c concreteFoo) String() string {
	return "concreteFoo"
}

type stringer interface {
	String() string
}

func takesAStringer(s stringer) {
	fmt.Println(s.String())
}

func main() {
	f := concreteFoo{}
	takesAStringer(f)
}

[Jacalz]

But the methods for the collectable types used within the project are all pointer receivers.

I don't see any reason for keeping the runtime check around for something that only can occur as a bug on the developer side and is checked by the compiler in our case as all types use pointer receivers (like is most usual in Go code over all).

[psanford]

I would take this change If you wrote a static analysis test that showed that every implementation of this interface used pointer types.

[Jacalz]

I've pushed a commit to at least not get the value twice from msg using reflect. It should be better than nothing in the meantime.

[Jacalz]

I might actually have a better fix for this. Will see what I can do.

[Jacalz]

I have opened #95 with a different approach that checks the struct pointer in a different way without using the reflect package at all. If that PR is rejected, this is still a nice improvement over the previous code.

[psanford]

Can you squash this into a single commit?

[Jacalz]

Done

[Jacalz]

Ping @psanford