add logs to debug

Author: sakthivelmanii

google-cloud-spanner/src/main/java/com/google/cloud/spanner/MultiplexedSessionDatabaseClient.java

@@ -39,6 +39,7 @@
 import java.time.Clock;
 import java.time.Duration;
 import java.time.Instant;
+import java.time.temporal.ChronoUnit;
 import java.util.BitSet;
 import java.util.EnumSet;
 import java.util.HashMap;
@@ -417,24 +418,25 @@ void setPool(SessionPool pool) {
   }
 
   private void maybeWaitForSessionCreation(
-      SessionPoolOptions sessionPoolOptions, SettableApiFuture<SessionReference> initialSessionReferenceFuture) {
+      SessionPoolOptions sessionPoolOptions,
+      SettableApiFuture<SessionReference> initialSessionReferenceFuture) {
     Duration waitDuration = sessionPoolOptions.getWaitForMinSessions();
     SpannerException lastException = null;
     SettableApiFuture<SessionReference> sessionReferenceFuture = initialSessionReferenceFuture;
 
     if (waitDuration != null && !waitDuration.isZero()) {
-      Instant endTime = Instant.now().plus(waitDuration);
-      while (Instant.now().isBefore(endTime)) {
+      Instant endTime = Instant.now().plus(waitDuration).truncatedTo(ChronoUnit.MILLIS);
+      Duration remainingTime;
+      while ((remainingTime = Duration.between(Instant.now(), endTime)).toMillis() > 0) {
         // If any exception is thrown, then retry the multiplexed session creation
         if (sessionReferenceFuture == null) {
           sessionReferenceFuture = SettableApiFuture.create();
           asyncCreateMultiplexedSession(sessionReferenceFuture);
           this.multiplexedSessionReference.set(sessionReferenceFuture);
         }
         // Calculate the remaining time pending for the future to wait for multiplexed session
-        Duration remainingTime = Duration.between(Instant.now(), endTime);
         System.out.println("Is ended: " + Instant.now().isBefore(endTime));
-        System.out.println("Remaining time: " + remainingTime.toMillis());
+        System.out.println("Remaining time: " + remainingTime.toNanos());
         try {
           sessionReferenceFuture.get(remainingTime.toMillis(), TimeUnit.MILLISECONDS);
           lastException = null;