针对"Apollo GraphQL Subscriptions: Use separate subscription resolvers for create, update, and delete or use a single resolver?"的问题，以下是两种解决方法的示例代码：

1. 使用单个订阅解析器：

const { ApolloServer, PubSub } = require('apollo-server');
const pubsub = new PubSub();

const typeDefs = `
  type Message {
    id: ID!
    content: String!
  }

  type Query {
    messages: [Message]
  }

  type Mutation {
    createMessage(content: String!): Message
    updateMessage(id: ID!, content: String!): Message
    deleteMessage(id: ID!): ID
  }

  type Subscription {
    messageCreated: Message
    messageUpdated: Message
    messageDeleted: ID
  }
`;

const messages = [];

const resolvers = {
  Query: {
    messages: () => messages,
  },
  Mutation: {
    createMessage: (_, { content }) => {
      const newMessage = { id: messages.length + 1, content };
      messages.push(newMessage);
      pubsub.publish('MESSAGE_CREATED', { messageCreated: newMessage });
      return newMessage;
    },
    updateMessage: (_, { id, content }) => {
      const messageIndex = messages.findIndex(message => message.id === id);
      if (messageIndex === -1) {
        throw new Error('Message not found');
      }
      const updatedMessage = { ...messages[messageIndex], content };
      messages[messageIndex] = updatedMessage;
      pubsub.publish('MESSAGE_UPDATED', { messageUpdated: updatedMessage });
      return updatedMessage;
    },
    deleteMessage: (_, { id }) => {
      const messageIndex = messages.findIndex(message => message.id === id);
      if (messageIndex === -1) {
        throw new Error('Message not found');
      }
      messages.splice(messageIndex, 1);
      pubsub.publish('MESSAGE_DELETED', { messageDeleted: id });
      return id;
    },
  },
  Subscription: {
    messageCreated: {
      subscribe: () => pubsub.asyncIterator('MESSAGE_CREATED'),
    },
    messageUpdated: {
      subscribe: () => pubsub.asyncIterator('MESSAGE_UPDATED'),
    },
    messageDeleted: {
      subscribe: () => pubsub.asyncIterator('MESSAGE_DELETED'),
    },
  },
};

const server = new ApolloServer({
  typeDefs,
  resolvers,
});

server.listen().then(({ url }) => {
  console.log(`Server ready at ${url}`);
});

2. 使用不同的订阅解析器：

const { ApolloServer, PubSub } = require('apollo-server');
const pubsub = new PubSub();

const typeDefs = `
  type Message {
    id: ID!
    content: String!
  }

  type Query {
    messages: [Message]
  }

  type Mutation {
    createMessage(content: String!): Message
    updateMessage(id: ID!, content: String!): Message
    deleteMessage(id: ID!): ID
  }

  type Subscription {
    messageCreated: Message
    messageUpdated(id: ID!): Message
    messageDeleted(id: ID!): ID
  }
`;

const messages = [];

const resolvers = {
  Query: {
    messages: () => messages,
  },
  Mutation: {
    createMessage: (_, { content }) => {
      const newMessage = { id: messages.length + 1, content };
      messages.push(newMessage);
      pubsub.publish('MESSAGE_CREATED', { messageCreated: newMessage });
      return newMessage;
    },
    updateMessage: (_, { id, content }) => {
      const messageIndex = messages.findIndex(message => message.id === id);
      if (messageIndex === -1) {
        throw new Error('Message not found');
      }
      const updatedMessage = { ...messages[messageIndex], content };
      messages[messageIndex] = updatedMessage;
      pubsub.publish('MESSAGE_UPDATED', { messageUpdated: updatedMessage });
      return updatedMessage;
    },
    deleteMessage: (_, { id }) => {
      const messageIndex = messages.findIndex(message => message.id === id);
      if (messageIndex === -1) {
        throw new Error('Message not found');
      }
      messages.splice(messageIndex, 1);
      pubsub.publish('MESSAGE_DELETED', { messageDeleted: id });
      return id;
    },
  },
  Subscription: {
    messageCreated: {
      subscribe: () => pubsub.asyncIterator('MESSAGE_CREATED'),
    },
    messageUpdated: {
      subscribe: (_, { id }) => pubsub.asyncIterator(`MESSAGE_UPDATED_${id}`),
    },
    messageDeleted: {
      subscribe: (_, { id }) => pubsub.asyncIterator(`MESSAGE_DELETED_${id}`