null exception

Author: surbhigarg92

google-cloud-spanner/src/main/java/com/google/cloud/spanner/spi/v1/HeaderInterceptor.java

@@ -169,7 +169,9 @@ private void processHeader(
 
         spannerRpcMetrics.recordGfeLatency(gfeLatency, attributes);
         spannerRpcMetrics.recordGfeHeaderMissingCount(0L, attributes);
-        compositeTracer.recordGFELatency(gfeLatency);
+        if (compositeTracer != null) {
+          compositeTracer.recordGFELatency(gfeLatency);
+        }
 
         if (span != null) {
           span.setAttribute("gfe_latency", String.valueOf(gfeLatency));