Request: Adding used Memory during span. #120
Description
First of all, thanks for the project and bringing OpenTelemetry to the julia language.
It helps massively with debugging a Webserver application written in julia.
One thing I am missing or rather would help to debug is adding the used memory during a span in addition to the already present time.
This could be integrated into the with_span("Hello, World!") with the @allocated Macro (https://m3g.github.io/JuliaNotes.jl/stable/memory/).
Is there a simple way to extend the function on the app side to integrate this without requiring any changes to the OpenTelemetryAPI?