Track cross-thread control-flow events

One of the core Go proverbs is, "Don't communicate by sharing memory; share memory by communicating." One of the core language features of Go is channels. Channels are effectively a concurrency-safe FIFO used to pass messages and for synchronization. This effectively means Go has a cross-thread, control-flow mechanism. Certain Go-based systems are built as a collection of components or modules executing concurrently, making heavy use of channels for message passing, synchronization, and control-flow. This makes it very difficult to debug events that involve channels. Two examples are Tendermint and libp2p.

I want a way to track these cross-thread, control-flow events in the debugger. So, some kind of cross-linking between threads indicating the flow of events. I don't know how this can be done but it would be amazingly useful so I want to start a discussion. For this to be useful, VSCode would need to implement some front-end, and Delve (the Go debugger) would need to implement some back-end, but I figured a good first step is building a conceptual framework for how it would work. CC @connor4312 @hyangah