Allow setting NIOSSLCustomVerificationCallback for NIOSSLServerHandler

[toffaletti]

Background for why this is useful and when it was added to NIOSSL: apple/swift-nio-ssl#25

Currently there is no way to pass this argument when the NIOSSLServerHandler is created:

hummingbird/Sources/HummingbirdHTTP2/HTTP2UpgradeChannel.swift

Line 94 in c1d1757

try channel.pipeline.syncOperations.addHandler(NIOSSLServerHandler(context: self.sslContext))

Relevant docs on NIOSSLServerHandler:
https://swiftinit.org/docs/swift-nio-ssl/niossl/niosslserverhandler.init(context:customverificationcallback:configuration:)

https://swiftinit.org/docs/swift-nio-ssl/niossl/niosslserverhandler#s:6NIOSSL19NIOSSLServerHandlerC7context26customVerificationCallback13configurationAcA13NIOSSLContextC_ySayAA17NIOSSLCertificateCG_7NIOCore16EventLoopPromiseVyAA24NIOSSLVerificationResultOGtcSgAA13NIOSSLHandlerC13ConfigurationVtcfc

[toffaletti]

Perhaps a closure can be passed optionally in the HTTP2ChannelConfiguration or () -> NIOSSLServerHandler

hummingbird/Sources/HummingbirdHTTP2/HTTP2Channel.swift

Line 24 in c1d1757

public struct HTTP2ChannelConfiguration: Sendable {

Or perhaps there is some callback I could use to remove the NIOSSLServerHandler provided by HTTP2UpgradeChannel and add one I created?

[adam-fowler]

This should be easy enough to add in some form. Let me have a look

[adam-fowler]

So we have PR #673 which adds a TLSChannelConfiguration to the HTTP2 and TLS channels. This is setting the custom verification but then it never seems to get called. I don't know if you want to test this

EDIT: Got the tests working. Forgot to set certificate verification on server TLSConfiguration

[toffaletti]

Awesome! I'm working on something else right now, but I'll try to test this soon.

[adam-fowler]

In 2.9.0