test: Add benchmark with many log entry fields.

Change-Id: I9ef4ff2bc0ccd8c0b674b9e8cd0c1e93fbe445ff
diff --git a/core/src/test/java/eu/mulk/quarkus/googlecloud/jsonlogging/FormatterBenchmark.java b/core/src/test/java/eu/mulk/quarkus/googlecloud/jsonlogging/FormatterBenchmark.java
index 1a1c17c..4900a01 100644
--- a/core/src/test/java/eu/mulk/quarkus/googlecloud/jsonlogging/FormatterBenchmark.java
+++ b/core/src/test/java/eu/mulk/quarkus/googlecloud/jsonlogging/FormatterBenchmark.java
@@ -13,12 +13,14 @@
 
   private ExtLogRecord simpleLogRecord;
   private ExtLogRecord structuredLogRecord;
+  private ExtLogRecord massivelyStructuredLogRecord;
   private Formatter formatter;
 
   @Setup
   public void setup() {
     simpleLogRecord = FormatterTest.makeSimpleRecord();
     structuredLogRecord = FormatterTest.makeStructuredRecord();
+    massivelyStructuredLogRecord = FormatterTest.makeMassivelyStructuredRecord();
     formatter = new Formatter(List.of(), List.of());
   }
 
@@ -31,4 +33,10 @@
   public void structuredLogRecord(Blackhole blackhole) {
     blackhole.consume(formatter.format(structuredLogRecord));
   }
+
+  @Benchmark
+  public void massivelyStructuredLogRecord(Blackhole blackhole) {
+    var f = formatter.format(massivelyStructuredLogRecord);
+    blackhole.consume(f);
+  }
 }