mysql Nodejs pool.getConnection returns undefined

Question

I am trying to recreate mysql Nodejs transaction using async await syntax. This is what the documentation shows without async/await:

connection.beginTransaction(function(err) {
  if (err) { throw err; }
  connection.query('INSERT INTO posts SET title=?', title, function (error, results, fields) {
    if (error) {
      return connection.rollback(function() {
        throw error;
      });
    }

    var log = 'Post ' + results.insertId + ' added';

    connection.query('INSERT INTO log SET data=?', log, function (error, results, fields) {
      if (error) {
        return connection.rollback(function() {
          throw error;
        });
      }
      connection.commit(function(err) {
        if (err) {
          return connection.rollback(function() {
            throw err;
          });
        }
        console.log('success!');
      });
    });
  });
});

I have created an async pool that I can use with async await:

let util=require('util')

let pool = mysql.createPool({
    connectionLimit: 20,
    host: keys.connection.host,
    user: keys.connection.user,
    password: keys.connection.password,
    database: keys.connection.database,
    dateStrings: true 
    // debug:true                //Set this to true for verbose debugging. Leaving this to default for now cause it is creating too many messages at my console
})
pool.getConnection((err, connection) => {
    if (err) {
        if (err.code === 'PROTOCOL_CONNECTION_LOST') {
            console.error('Database connection was closed.')
        }
        if (err.code === 'ER_CON_COUNT_ERROR') {
            console.error('Database has too many connections.')
        }
        if (err.code === 'ECONNREFUSED') {
            console.error('Database connection was refused.')
        }
    }
    if (connection) connection.release()
    return
})

pool.query = util.promisify(pool.query)

module.exports = pool

To convert the documentation to async/await I tried to do :

const connection = await pool.getConnection();
await connection.beginTransaction();

but I am getting:

TypeError: Cannot read property 'beginTransaction' of undefined