message: Add usage instructions for `SIGUSR1` queue dumping to `README.md`
diff: @@ -186,6 +186,46 @@ modules in `components`, and `warn` level for the remaining codebase:
  RUST_LOG=casper_node::components::small=trace,casper_node::comp=info,warn
  ```
  +## Debugging
  +
  +Some additional debug functionality is available, mainly allowed for inspections of the internal event queue.
  +
  +### Event queue dump
  +
  +The event queue can be dumped by sending a `SIGUSR1` to the running node process, e.g. if the node's process ID was `$NODE_PID`:
  +
  +```console
  +kill -USR1 $NODE_PID
  +```
  +
  +This will create a `queue_dump.json` in the working directory of the node. A tool like [jq](https://stedolan.github.io/jq/) can then be used to format and display it:
  +
  +```console
  +$ jq < queue_dump.json
  +{
  + "NetworkIncoming": [],
  + "Network": [],
  + "Regular": [
  + "AddressGossiper"
  + ],
  + "Api": []
  +}
  +```
  +
  +#### jq Examples
  +
  +Dump the type of events:
  +
  +```console
  +jq 'map_values( map(keys[0] | {"type": ., weight: 1})| group_by(.type) | map ([.[0].type,(.|length)]) | map({(.[0]): .[1]}) )' queue_dump.json
  +```
  +
  +Count number of events in each queue:
  +
  +```console
  +jq 'map_values(map(keys[0]))' queue_dump.json
  +```
  +
  ## Running a client
  See [the client README](client/README.md).
  