Fix WriteConcernProseTest errors
package com.mongodb.internal.async.client;
-import com.mongodb.MongoException;
import com.mongodb.MongoNamespace;
import com.mongodb.MongoWriteConcernException;
import com.mongodb.async.FutureResultCallback;
@@ -31,8 +30,6 @@ import org.bson.codecs.DocumentCodec;
import org.junit.Before;
import org.junit.Test;
-import java.util.concurrent.TimeUnit;
-
import static com.mongodb.ClusterFixture.isDiscoverableReplicaSet;
import static com.mongodb.ClusterFixture.serverVersionAtLeast;
import static com.mongodb.internal.async.client.Fixture.getDefaultDatabaseName;
