Making a manual mode of operation for measurements, where you can manually call start() and stop() instead of using the function-call syntax
This is especially useful to take measurements that span multiple test steps, or where you need to have different operations fall under the same measurement

An example of use is in the formatters perf test case

git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@177597 91177308-0d34-0410-b5e6-96231b3b80d8