add getter for session transport protocol

[Morfent]

This is useful when diagnosing issues with SockJS that may be related to what
kind of protocol a connection is using.

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This change is 

[coveralls]

Coverage decreased (-0.6%) to 94.839% when pulling 76d8609 on Morfent:transport into 1f275fb on igm:master.

[Morfent]

Added unit tests

[coveralls]

Coverage increased (+0.03%) to 95.484% when pulling 5748021 on Morfent:transport into 1f275fb on igm:master.

[FZambia]

Hi, why not just call path.Base(s.Request().URL.Path) in you app code? It's not difficult and this way we don't introduce new method to Session interface.

[Morfent]

It's not difficult, but it won't always be clear to others reading that code that the end of the URL is going to be the protocol unless they're pretty familiar with SockJS. I think it'd also help with people transferring code from sockjs-node since protocols are just properties on session objects in that package.

[FZambia]

Sounds reasonable 👍

[igm]

not sure if this PR is still relevant and demanded. I generally prefer not to change interfaces.

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Review status: 0 of 3 files reviewed at latest revision, all discussions resolved.

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sockjs/session.go, line 227 at r1 (raw file):

func (s *session) Protocol() string {
	protocol := path.Base(s.req.URL.Path)

would it be sufficient to put session as a parameter instead of receiver?

func Protocol(s Session) string {
	protocol := path.Base(s.Request().URL.Path)
	return protocol
}

This does not change session interface

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Comments from Reviewable

[igm]

fixed in v3