Use AtomicTimer for more accurate local solution rate

src/miner.cpp

@@ -528,12 +528,14 @@ void static BitcoinMiner()
             cancelSolver = true;
         }
     );
+    miningTimer.start();
 
     try {
         while (true) {
             if (chainparams.MiningRequiresPeers()) {
                 // Busy-wait for the network to come online so we don't waste time mining
                 // on an obsolete chain. In regtest mode we expect to fly solo.
+                miningTimer.stop();
                 do {
                     bool fvNodesEmpty;
                     {
@@ -544,6 +546,7 @@ void static BitcoinMiner()
                         break;
                     MilliSleep(1000);
                 } while (true);
+                miningTimer.start();
             }
 
             //
@@ -721,16 +724,19 @@ void static BitcoinMiner()
     }
     catch (const boost::thread_interrupted&)
     {
+        miningTimer.stop();
         c.disconnect();
         LogPrintf("ZcashMiner terminated\n");
         throw;
     }
     catch (const std::runtime_error &e)
     {
+        miningTimer.stop();
         c.disconnect();
         LogPrintf("ZcashMiner runtime error: %s\n", e.what());
         return;
     }
+    miningTimer.stop();
     c.disconnect();
 }