Types for Email Workers

Does anyone know where to go to get the types for email workers?

export default {
  async email(message, env, ctx) {
    // stuff
  }
}

export default {
  async email(message, env, ctx) {
    // stuff
  }
}

export default {
  async email(message, env, ctx) {
    // stuff
  }
}

export default {
  async email(message, env, ctx) {
    // stuff
  }
}