[Seaside] Server-Timing filter goodie

[Sven Van Caekenberghe]

> On 10 Jul 2020, at 15:48, Esteban Maringolo <emaringolo at gmail.com> wrote:
> 
> Note: I think there is a bug in the conversion of the headers from a
> WAResponse to ZnResponse in ZnZincServerAdaptor, since if there are
> several headers with the same name in aWAResponse, but only the last
> one remains in ZnResponse, because it does an `at:put` instead of
> adding several headers or merging them all together (as with the
> 'Set-Cookie' header).

Yes, from the first look of it, that seems to be correct.

In ZnZincServerAdaptor>>#responseFrom: aRequestContext

	partialHeaders keysAndValuesDo: [ :key :value |
		fullHeaders at: key put: value greaseString ].

should be

	partialHeaders keysAndValuesDo: [ :key :value |
		fullHeaders at: key add: value greaseString ].

Sven