Add `Hint` support to beforeSend and Event processors

[lawrence-laz]

Hi, Sentry is great!
I am however missing a way to add an attachment to an outgoing event in the BeforeSend callback.
For example:

using var host = Host.CreateDefaultBuilder()
    .ConfigureLogging((context, builder) =>
    {
        builder.AddSentry(options =>
        {
            options.BeforeSend = sentryEvent =>
            {
                sentryEvent.AddBreadcrumb("Hello"); // I can do this
                sentryEvent.AddAttachment("Foo.txt"); // But I cannot do this
                return sentryEvent;
            };
        };
    })
    .Build();

Am I missing something, or this is a missing feature?

[bruno-garcia]

One solution to this is adding Hint which is part of the unified API spec: https://develop.sentry.dev/sdk/unified-api/#hints
Recently the Java SDK for hint as Map<string,object>: getsentry/sentry-java#1929

[pistoleta]

It would be great to have this

[bruno-garcia]

Blocks getsentry/sentry-unity#492