Package profile provides a simple method for exposing profile information
through a --cpu_profile flag. This package also implicitly adds the
/debug/pprof/... HTTP handlers.
Start begins profiling the program, writing data to the file given with the
--cpu_profile flag. If --cpu_profile was not given, nothing happens. Start
must not be called again until Stop is called. The profile data in the
--cpu_profile flag is overwritten on each call to Start.