[Haskell-cafe] "mapping" an Enumerator

[Kannan Goundan]

I'm using the Data.Enumerator library.  I'm trying to write a "map"
function that converts an Enumerator of one type to another.
Something like:

   mapEnum :: Monad m =>
          (a -> b) ->
          Enumerator a m r ->
          Enumerator b m r

Any hints?

(My exact use case is that I have a ByteString enumerator and I
need to pass it to something that requires a Blaze.Builder
enumerator.)