Close the file that the instrumentation profiler writes delta values to. The file must previously have been opened using open_delta_file/1.
Delta values are the instrumentation profiling results for the single execution (as opposed to aggregated) of a profiled code fragment.
For performance reasons, the results are written to the file using buffered I/O - each result is not flushed to the file as it is emitted. As a result to ensure all results are flushed to the disk file, close_delta_file must be executed.