Jenkins脚本管道- switch语句中变量的更改不会反映在管道步骤中

pipeline {
    agent any
    variables {
        String myVar = 'initial'
    }
    stages {
        stage('Switch Example') {
            steps {
                script {
                    switch (myVar) {
                        case 'initial':
                            myVar = 'changed'
                            break
                        case 'changed':
                            echo "Variable is now: ${myVar}"
                            break
                    }
                }
            }
        }
        stage('Verify Change') {
            steps {
                echo "Final variable value: ${myVar}"
            }
        }
    }
}

pipeline {
    agent any
    stages {
        stage('Set Variable') {
            steps {
                script {
                    withCredentials([string(credentialsId: 'my-credential-id', variable: 'MY_VAR')]) {
                        MY_VAR = 'changed'
                    }
                }
            }
        }
        stage('Verify Change') {
            steps {
                environment {
                    MY_VAR = "${MY_VAR}"
                }
                echo "Final variable value: ${MY_VAR}"
            }
        }
    }
}