docs: public ImmutableMap<TypeVariableSymbol, Nullness> getNullnessGenerics(
        MethodInvocationTree callsite) {
      ImmutableMap.Builder<TypeVariableSymbol, Nullness> result = ImmutableMap.builder();
      for (TypeVariableSymbol tvs :
          TreeInfo.symbol((JCTree) callsite.getMethodSelect()).getTypeParameters()) {
        InferenceVariable iv = TypeVariableInferenceVar.create(tvs, callsite);
        if (constraintGraph.nodes().contains(iv)) {
          getNullness(iv).ifPresent(nullness -> result.put(tvs, nullness));
        }
      }
      return result.build();
    }