docs: private static void writeModel(DataOutputStream out) throws IOException {
      Map<String, String> importedAnnotations =
          ImmutableMap.<String, String>builder()
              .put("Nonnull", "javax.annotation.Nonnull")
              .put("Nullable", "javax.annotation.Nullable")
              .build();
      Map<String, Set<String>> packageAnnotations = new HashMap<>();
      Map<String, Set<String>> typeAnnotations = new HashMap<>();
      Map<String, MethodAnnotationsRecord> methodRecords = new LinkedHashMap<>();
  
      for (Map.Entry<String, Set<Integer>> entry : map_result.entrySet()) {
        String sign = entry.getKey();
        Set<Integer> ddParams = entry.getValue();
        if (ddParams.isEmpty()) continue;
        Map<Integer, ImmutableSet<String>> argAnnotation =
            new HashMap<Integer, ImmutableSet<String>>();
        for (Integer param : ddParams) {
          argAnnotation.put(param, ImmutableSet.of("Nonnull"));
        }
        methodRecords.put(
            sign,
            new MethodAnnotationsRecord(
                nullableReturns.contains(sign) ? ImmutableSet.of("Nullable") : ImmutableSet.of(),
                ImmutableMap.copyOf(argAnnotation)));
        nullableReturns.remove(sign);
      }
      for (String nullableReturnMethodSign : Iterator2Iterable.make(nullableReturns.iterator())) {
        methodRecords.put(
            nullableReturnMethodSign,
            new MethodAnnotationsRecord(ImmutableSet.of("Nullable"), ImmutableMap.of()));
      }
      StubxWriter.write(out, importedAnnotations, packageAnnotations, typeAnnotations, methodRecords);
    }