Always attach a stack trace, when AttachStackTrace is true

[mattjohnsonpint]

Problem Statement

The current behavior SentryOptions.AttachStackTrace = true is that we attach a stack trace when capturing any error event that does not contain an exception.

This does not cover the case where there is an exception on the event, but it does not contain a stack trace.

For example:

SentrySdk.CaptureException(new Exception("test"));

Regardless of the AttachStackTrace option, no stack trace will be sent.

Solution Brainstorm

AttachStackTrace = true implies that there should always be a stack trace. Thus, we can check the exceptions on the event and see if any of them have a stack trace. If none do, then attach one separately.

Note that the stack trace will point at where the exception is captured, not where it is created.

In other words, it's different than throwing and capturing the exception like this:

try
{
    throw new Exception("test");
}
catch (Exception exception)
{
    SentrySdk.CaptureException(exception);
}

In that case, the stack trace will point at where the exception is thrown.

Still, it's better to have some stack trace than nothing, IMHO.