如何在Vuetify日期选择器中添加附加字段？

<template>
  <v-app>
    <v-date-picker v-model="selectedDate" @input="updateAdditionalField"></v-date-picker>
    <p>附加字段: {{ additionalField }}</p>
  </v-app>
</template>

<script>
export default {
  data() {
    return {
      selectedDate: null,
      additionalField: ''
    };
  },
  methods: {
    updateAdditionalField() {
      // 在这里更新附加字段的值
      this.additionalField = '附加字段内容';
    }
  }
};
</script>

<template>
  <v-app>
    <v-date-picker v-model="selectedDate" @input="updateAdditionalField">
      <template v-slot:date="{ date }">
        <div>
          <span>{{ date }}</span>
          <span>{{ additionalField }}</span>
        </div>
      </template>
    </v-date-picker>
  </v-app>
</template>