first working version with simple instrumentation
use bloom filters to deduplicate log entries
improve documentation
add support for throttling logging to a % of evaluations
switch to statically allocated placeholder stack
improve handling of exceptions during placeholder evaluation
buffer writes to avoid calling clog.log_line many times
add calls to FLUSH in CheetahTemplate.getVar/hasVar
get the deploy SHA from Python (util.version), not the filename
refactor code for easier testing
redesign logging & add timing info
add test code
reset timers on every instrumentStartRequest()
refactor a bit and add more comments
add more error handling and tests
delay instrumentInit() until first instrumentStartRequest()
add tests for placeholder stack and log buffer overflows
fix handling of exceptions
minor fixes to exception handling
remove an extra COUNT(Placeholder)