code: @Nullable
      protected final <T> T jsiiCall(final String method, final Class<T> returnType, @Nullable final Object... args) {
          return JsiiObjectMapper.treeToValue(JsiiObject.engine.getClient()
                                                                  .callMethod(this.objRef,
                                                                              method,
                                                                              JsiiObjectMapper.valueToTree(args)),
                                              returnType);
      }
docs: Calls a JavaScript method on the object.
  @param method The name of the method.
  @param returnType The return type.
  @param args Method arguments.
  @param <T> Java type for the return value.
  @return A return value.