It seems that the groovy client doesn't work well

Description

I generate groovy client, and find out that the post method doesn't attach any post body with the request.
As a result the request post with no body data.
Let me excerpt some piece of code generated:

        //method excerpted from pet store sample
        def createUsersWithArrayInput ( List<User> body, Closure onSuccess, Closure onFailure)  {
       
        // create path and map variables
        String resourcePath = "/user/createWithArray"

        // query params
        def queryParams = [:]
        def headerParams = [:]
    
        // verify required params are set
        if (body == null) {
            throw new RuntimeException("missing required params body")
        }

        invokeApi(onSuccess, onFailure, basePath, versionPath, resourcePath, queryParams, headerParams,
                    "POST", "",
                    null )
                    
    }

we can see that the body is validated not null. and that's all for the body.
In no way the body is attached in the request.
Is there anyone can explain?

Swagger-codegen version

the code is generate via swagger online tool

Swagger declaration file content or url

  /user/createWithArray:
    post:
      tags:
        - user
      summary: Creates list of users with given input array
      description: ''
      operationId: createUsersWithArrayInput
      produces:
        - application/xml
        - application/json
      parameters:
        - in: body
          name: body
          description: List of user object
          required: true
          schema:
            type: array
            items:
              $ref: '#/definitions/User'
      responses:
        default:
          description: successful operation

Command line used for generation

groovy

Steps to reproduce

just generate groovy client code with definition from https://github.com/vorburger/swagger-codegen-gradle-plugin-example/blob/master/petstore-swagger.json via the online swagger generator

Reproduce the issue with the linked petstore Swagger definition and the online Groovy generator, then trace the generated invokeApi call shown in the excerpt. Confirm the generated POST client includes the required body data in the request and add or update coverage for this body parameter behavior.