add attribute extractor back to singletons

Author: jaydeluca

instrumentation/couchbase/couchbase-2.0/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/couchbase/v2_0/CouchbaseSingletons.java

@@ -14,6 +14,7 @@
 import io.opentelemetry.instrumentation.api.instrumenter.SpanKindExtractor;
 import io.opentelemetry.instrumentation.api.instrumenter.SpanNameExtractor;
 import io.opentelemetry.instrumentation.api.semconv.network.NetworkAttributesExtractor;
+import io.opentelemetry.javaagent.bootstrap.internal.AgentInstrumentationConfig;
 
 public final class CouchbaseSingletons {
 
@@ -37,6 +38,11 @@ public final class CouchbaseSingletons {
                     CouchbaseRequestInfo.init(context, couchbaseRequest))
             .addOperationMetrics(DbClientMetrics.get());
 
+    if (AgentInstrumentationConfig.get()
+        .getBoolean("otel.instrumentation.couchbase.experimental-span-attributes", false)) {
+      builder.addAttributesExtractor(new ExperimentalAttributesExtractor());
+    }
+
     INSTRUMENTER = builder.buildInstrumenter(SpanKindExtractor.alwaysClient());
   }