Add license header

hapi-fhir-server/src/main/java/ca/uhn/fhir/rest/server/ServletRequestTracing.java

@@ -1,5 +1,25 @@
 package ca.uhn.fhir.rest.server;
 
+/*-
+ * #%L
+ * HAPI FHIR - Server Framework
+ * %%
+ * Copyright (C) 2014 - 2021 Smile CDR, Inc.
+ * %%
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * #L%
+ */
+
 import ca.uhn.fhir.rest.api.Constants;
 import org.apache.commons.lang3.RandomStringUtils;
 import org.slf4j.Logger;