Commented Issue: Implement OWIN host buffer policy correctly [1418]

OWIN exposes ways to disable request and response buffering, but we don't use them. That means we'll always get buffered versions of these streams on hosts like IIS. We should use these OWIN mechanisms when they're available and the Web API buffer policy says don't buffer.
Comments: commit 430b5f33055c26bbee347457275f13c20d565a89