Resolve address via a function

[vcostet]

Similarly to what's done on the java client (here), add a way to resolve addresses using a function, instead of a static value.

var streamSystem = await StreamSystem.Create(
    new StreamSystemConfig()
    {
        UserName = "myuser",
        Password = "mypassword",
        AddressResolver = new AddressResolverDynamic((host, port) => {
            // Is called after getting the stream leader/replica host
            // and port, and before trying to connect to them
            return new IPEndPoint(IPAddress.Parse("xxx.xxx.xxx.xxx"));
        }),
        Endpoints = new List<EndPoint> {endpoint1}
    }
);

AddressResolver attribute on StreamSystemConfig has been changed to an interface, so the existing AddressResolver class can still be used.

[Gsantomaggio]

Thank you, @vcostet. Can you please check the CI errors?

[vcostet]

Should be good, at least for the build part. I put back the Endpoint attribute to public on AddressResolver.

[Zerpet]

Hi @vcostet 👋 Thank you for contributing to this client. Recently (a month ago) our company did some changes around open source contribution, and now it's required that you sign a contributor license agreement (CLA) before we can accept your PR.

The process is explained here in this repo README: https://github.com/rabbitmq/cla

Would you review and sign this CLA?

[Zerpet]

Blocking merge on CLA signing. Code looks good.

[Gsantomaggio]

@vcostet just a reminder about the CLA :)

[Gsantomaggio]

Sorry @vcostet, if you can't sign the CLA, I am afraid I have to close the PR.
thank you

[vcostet]

Hi,

I didn't mention it here, but I have signed it on Sept. 23.

[Zerpet]

CLA received on September 23rd, thank you! It took us a bit to correlate the signing with this PR 🙃

CLA signed

[Gsantomaggio]

Thank you @vcostet @Zerpet