Markup

I'm become uncomfortable with the wide use of "async", particularly in
the markup (but also in the general discussion).  The term "async"
refers to (at least) two separate things:

    * The client code using a callback instead of waiting for a method
      return.
    * The server being able to send a response elsewhere than the
      transport's built-in response channel.

I would prefer that the WSDL describing the server take the server's
point of view:

    * Rename the "AsyncOnly" flag (or async="always") to
      "NoDirectResponse" (or "DirectResponse=false", default being true)
    * I had previously mentioned having the Async element carry one or
      the other (but not both) of "ProtocolBinding" or "WsdlBinding". 
      Instead, have UsingAddressing take one or the other (but not both)
      of the following child elements:
          o <ResponseProtocol>anyIRI</ResponseProtocol>
          o <ResponseBinding>qname</ResponseBinding>
    * As before, ResponseProtocol would be defined as shorthand for a
      ResponseBinding with the desired effect.