Trying to use a Span's data inside the span

[SamedhG]

I have a project that does a bunch of asynchronous stuff based on web requests. I want to use correlation IDs to match the incoming request with other related outgoing requests.
My plan is to use HTTP headers.

1. A request comes in I get the correlation ID from the header and place that as an extension in my root span.
2. Each new span created picks up the correlation ID from it's parent.
3. I get the correlation ID of the current span and pass it in the HTTP headers of any further requests I make.

I can get to the point where the data is correctly stored in the span and logged with the message, but I cannot get the data out in the middle of the span. Any suggestions on how I could solve this. Or if there is a better design to store and manage these correlation IDs.