Fix for CONPY-161:

Since resolution of time.monotonic() is not precise enough, we need to use
first connection in ConnectionPool.get_connection() method, in case all
values obtained by time.monotonic() are the same.

Author: 9EOR9

mariadb/connectionpool.py

@@ -157,7 +157,7 @@ def get_connection(self):
 
         now= time.monotonic()
         conn= None
-        timediff= 0
+        timediff= -1
 
         with self._lock_pool:
             for i in range(0, len(self._connections)):