rd
host ∷ B.ByteString -- ^ Hostname
     → Route ()
host h = getHeader "Host" >>= guard ∘ (≡) (Just h)
{-# INLINE hos
emptyPath ∷ Route ()
emptyPath = get >>= guard ∘ null ∘ reqPath ∘ fst
emptyPath = get >>= guard ∘ null ∘ reqPath ∘ fst