update() return last sync state

As the update() function return false both if the forceUpdate fail, and also if the timeout isn't expired, we are not able to know if the last ntp update was fine.
Wouldn't be better to return true if the last sync was gone ok, and false if wasn't good?

NTPClient.cpp

@@ -98,11 +98,15 @@ bool NTPClient::forceUpdate() {
   do {
     delay ( 10 );
     cb = this->_udp->parsePacket();
-    if (timeout > 100) return false; // timeout after 1000 ms
+    if (timeout > 100) {
+      this->_lastUpdateOk = false;
+      return false; // timeout after 1000 ms
+    }
     timeout++;
   } while (cb == 0);
 
   this->_lastUpdate = millis() - (10 * (timeout + 1)); // Account for delay in reading the time
+  this->_lastUpdateOk = true;
 
   this->_udp->read(this->_packetBuffer, NTP_PACKET_SIZE);
 
@@ -123,7 +127,7 @@ bool NTPClient::update() {
     if (!this->_udpSetup || this->_port != NTP_DEFAULT_LOCAL_PORT) this->begin(this->_port); // setup the UDP client if needed
     return this->forceUpdate();
   }
-  return false;   // return false if update does not occur
+  return this->_lastUpdateOk;   // return last sync state
 }
 
 unsigned long NTPClient::getEpochTime() const {

NTPClient.h

@@ -22,6 +22,7 @@ class NTPClient {
 
     unsigned long _currentEpoc    = 0;      // In s
     unsigned long _lastUpdate     = 0;      // In ms
+    bool          _lastUpdateOk   = false;  //
 
     byte          _packetBuffer[NTP_PACKET_SIZE];