the parameters that fn will also need
function that returns a ServiceFactory given params and a remote host
The description of the functionality of the element.
The description of the functionality of the element.
The Params that the element is interested in.
The Params that the element is interested in.
The Role that the element can serve.
The Role that the element can serve.
A module that hooks in a
ServiceFactorythat directly makes connections, intended to be used as the lastServiceFactoryin the stack, the endpointer.