Then chains the middleware and returns the final http.Handler.
New(m1, m2, m3).Then(h)
is equivalent to:
When the request comes in, it will be passed to m1, then m2, then m3 and finally, the given handler (assuming every middleware calls the following one).
A chain can be safely reused by calling Then() several times.
stdStack := alice.New(ratelimitHandler, csrfHandler) indexPipe = stdStack.Then(indexHandler) authPipe = stdStack.Then(authHandler)
Note that constructors are called on every call to Then() and thus several instances of the same middleware will be created when a chain is reused in this way. For proper middleware, this should cause no problems.
Then() treats nil as http.DefaultServeMux.