My point about `Body.length` throwing an exception...

# http4k

[xenomachina]

My point about Body.length throwing an exception is that this is the kind of thing that should be documented in the interface. Similarly, some information about when clients can expect a Body to be "used up" (eg: it looks like even using == on StreamBody consumes the stream) would be great, as well as guidance about when a Body needs to be "closed" (though that belongs at every site that returns/contains a Body, and anything that consumes a Body (or HttpMessage) needs to say whether it will become responsible for closing it.