time can not go backwards if it is monotonic

gmossessian · gmossessian · commit 5df1730ac9e2 · 2019-12-06T14:43:27.000-05:00
Signed-off-by: George Mossessian &lt;gmossessian@gmail.com&gt;
diff --git a/prometheus_client/context_managers.py b/prometheus_client/context_managers.py
@@ -1,6 +1,6 @@
 from __future__ import unicode_literals
 
-from timeit import default_timer
+from time import monotonic
 
 from .decorator import decorate
 
@@ -51,11 +51,10 @@ def _new_timer(self):
         return self.__class__(self._callback)
 
     def __enter__(self):
-        self._start = default_timer()
+        self._start = monotonic()
 
     def __exit__(self, typ, value, traceback):
-        # Time can go backwards.
-        duration = max(default_timer() - self._start, 0)
+        duration = monotonic() - self._start
         self._callback(duration)
 
     def __call__(self, f):
