Feature Request: Visualize Time Difference Across Spans (End–Start)

### Problem Statement We’ve recently created a new dashboard for one requirement and we are adding custom spans to our traces (for example, spans A, B, and C) and are using the dashboard to visualize their performance. Currently, the dashboard allows us to visualize combined spans (like the total time for A+B) by using addition. However, this approach also includes non-instrumented gaps between the spans, which makes it difficult to measure the precise interval we care about. Our requirement is to visualize the difference between two spans, specifically something like: B’s end time – A’s start time This would allow us to see the total duration covering a specific interval of interest across spans, rather than just aggregated or overlapping values. Would it be possible to add this feature to the dashboard, it would be very useful instead of creating separate spans for such use cases. ### Solution Brainstorm _No response_ ### Product Area Dashboards