add nullaway

Author: zeitlinger

instrumentation-api-incubator/src/main/java/io/opentelemetry/instrumentation/api/incubator/semconv/db/DbClientCommonAttributesGetter.java

@@ -5,6 +5,8 @@
 
 package io.opentelemetry.instrumentation.api.incubator.semconv.db;
 
+import static java.util.Objects.requireNonNull;
+
 import javax.annotation.Nullable;
 
 /** An interface for getting attributes common to database clients. */

instrumentation-api-incubator/src/main/java/io/opentelemetry/instrumentation/api/incubator/semconv/db/SqlClientAttributesGetter.java

@@ -40,6 +40,7 @@ default Collection<String> getRawQueryTexts(REQUEST request) {
   }
 
   // TODO: make this required to implement
+  @Nullable
   default Long getBatchSize(REQUEST request) {
     return null;
   }