AWS S3 SDK v3 - GetObjectCommandOutput - How to get the content from Readable

aws-s3-get-object-command-to-string.ts

const input:GetObjectRequest = {
    Bucket: this.eventsBucket,
    Key: `${request.eventName}/${request.eventId}`
}
const command = new GetObjectCommand(input);
const output = await this.s3Client.send(command)

let outputBody: string = ''
for await (let chunk of output.Body as Readable) {
    outputBody += chunk
}