Format sanitized bridge descriptors and Torperf measurement results
Stem has lots of code for parsing dir-spec.txt objects and metrics-related extensions. I could also make use of functionality to build objects, either based on previously parsed descriptors, or from scratch. I'd use this functionality to create sanitized bridge descriptors (where the order of keywords should be preserved, but where I can replace arguments or add/remove keywords), to format Torperf measurement results, etc. There would likely be just a single application using this code, but it seems useful to maintain this code together with the parsing code. There's no metrics-lib equivalent for this.