Correct a typo in sample code

explainer.md

@@ -64,7 +64,7 @@ An example code to use captureTimestamp and senderCaptureTimeOffset to calculate
     receiver = peerconnection.getReceivers()[0];
     csrc = receiver.getSynchronizationSources()[0];
     latestCaptureTimestamp = csrc.captureTimeStamp;
-    latestSenderCaptureTimeOffset = csrc.SenderCaptureTimeOffset;
+    latestSenderCaptureTimeOffset = csrc.senderCaptureTimeOffset;
     receiverTimestamp = csrc.timestamp;
 
     // Calculates sender-receiver clock offset from stats.