code: func (client *Client) CreateServiceInstance(spaceGUID, servicePlanGUID, serviceInstance string, parameters map[string]interface{}, tags []string) (ServiceInstance, Warnings, error) {
  	requestBody := createServiceInstanceRequestBody{
  		Name:            serviceInstance,
  		ServicePlanGUID: servicePlanGUID,
  		SpaceGUID:       spaceGUID,
  		Parameters:      parameters,
  		Tags:            tags,
  	}
  
  	bodyBytes, err := json.Marshal(requestBody)
  	if err != nil {
  		return ServiceInstance{}, nil, err
  	}
  
  	request, err := client.newHTTPRequest(requestOptions{
  		RequestName: internal.PostServiceInstancesRequest,
  		Body:        bytes.NewReader(bodyBytes),
  		Query:       url.Values{"accepts_incomplete": {"true"}},
  	})
  	if err != nil {
  		return ServiceInstance{}, nil, err
  	}
  
  	var instance ServiceInstance
  	response := cloudcontroller.Response{
  		DecodeJSONResponseInto: &instance,
  	}
  
  	err = client.connection.Make(request, &response)
  	return instance, response.Warnings, err
  }
docs: // CreateServiceInstance posts a service instance resource with the provided
  // attributes to the api and returns the result.