Add @type annotation to each Torperf measurement
According to the format description on the CollecTor website: "A Torperf results file contains a single line per Torperf run with key=value pairs. Such a result line is sufficient to learn about 1) the Tor and Torperf configuration, 2) measurement results, and 3) additional information that might help explain the results."
The Torperf Measurement Result files that CollecTor provides all start with a @type torperf 1.0 annotation, followed by one or more measurement lines. However, the correct way to do it is to include a @type torperf 1.0 annotation for each contained measurement.
The main reason is that each measurement is a descriptor in the sense that it describes what Torperf recorded for a single measurement. The fact that two or more such measurements end up in the same file is mostly random and only happens because it makes measurement results easier to handle. But the measurements that are contained in a file are not necessarily related, as it would be okay to just throw in all measurements from a given day or even month into a single file. The line is the descriptor, not the file, and that's why each line deserves its own @type annotation. This would be more obvious if measurements were to span multiple lines, but that doesn't mean that we can optimize the annotation away in the single-line case.
A possible reason against making this change is file size. I tested adding these annotations to the November 2015 tarball. The uncompressed tarball grew from 25904640 to 26491904 bytes (+2.3%), the compressed tarball grew from 2629336 to 2641308 bytes (+0.5%). This seems not crazy.
I'll post a simple branch that adds more @type annotations later today, and I'll replace existing tarballs with files that contain one such annotation per included line.