Hang the Jenkins workflow by loading a class with the load step

hang.groovy

// Content file:///home/martin/git/workflow-job-definition.git/hang.groovy
class MyClass implements Serializable {
  String name
  MyClass(String name) {
    this.name = name
  }
  String getName() {
    return "the name is: "+name
  }
  private void writeObject(ObjectOutputStream s) {
    s.defaultWriteObject()
    s.writeString(name)
  }
  private void readObject(ObjectInputStream s) {
    s.defaultReadObject()
    name = s.readString(name)
  }
}

MyClass createMyClass(String name) {
  return new MyClass(name)
}
return this

// Content of Jenkins job:
// Workflow job:
def flow
node() {
    git 'file:///home/martin/git/workflow-job-definition.git'
    flow = load 'hang.groovy'
}
def m = flow.createMyClass("Joe")
assert m.getName() == "Joe"