How to use the @aws-crypto/serialize.ContentType.FRAMED_DATA function in @aws-crypto/serialize

const material = await cmm.getEncryptionMaterials(encryptionRequest)
  const { kdfGetSubtleEncrypt, subtleSign, dispose } = await getEncryptHelper(material)

  const messageId = await backend.randomValues(MESSAGE_ID_LENGTH)

  const { id, ivLength } = material.suite

  const messageHeader: MessageHeader = {
    version: SerializationVersion.V1,
    type: ObjectType.CUSTOMER_AE_DATA,
    suiteId: id,
    messageId,
    encryptionContext: material.encryptionContext,
    encryptedDataKeys: material.encryptedDataKeys,
    contentType: ContentType.FRAMED_DATA,
    headerIvLength: ivLength,
    frameLength
  }

  const header = serialize.serializeMessageHeader(messageHeader)
  const info = kdfInfo(id, messageId)
  const getSubtleEncrypt = kdfGetSubtleEncrypt(info)

  const headerAuthIv = serialize.headerAuthIv(ivLength)
  const headerAuthTag = await getSubtleEncrypt(headerAuthIv, header)(new Uint8Array(0))

  const numberOfFrames = Math.ceil(plaintextLength / frameLength)
  /* The final frame has a variable length.
   * The value needs to be known, but should only be calculated once.
   * So I calculate how much of a frame I should have at the end.
   */

export function getEncryptionInfo (material : NodeEncryptionMaterial, frameLength: number) {
  const { kdfGetCipher } = getEncryptHelper(material)
  const { encryptionContext } = material

  const messageId = randomBytes(MESSAGE_ID_LENGTH)
  const { id, ivLength } = material.suite
  const messageHeader: MessageHeader = Object.freeze({
    version: SerializationVersion.V1,
    type: ObjectType.CUSTOMER_AE_DATA,
    suiteId: id,
    messageId,
    encryptionContext,
    encryptedDataKeys: Object.freeze(material.encryptedDataKeys), // freeze me please
    contentType: ContentType.FRAMED_DATA,
    headerIvLength: ivLength,
    frameLength
  })

  const { buffer, byteOffset, byteLength } = serializeMessageHeader(messageHeader)
  const headerBuffer = Buffer.from(buffer, byteOffset, byteLength)
  const info = kdfInfo(messageHeader.suiteId, messageHeader.messageId)
  const getCipher = kdfGetCipher(info)
  const headerIv = headerAuthIv(ivLength)
  const validateHeader = getCipher(headerIv)
  validateHeader.setAAD(headerBuffer)
  validateHeader.update(Buffer.alloc(0))
  validateHeader.final()
  const headerAuth = validateHeader.getAuthTag()

  return {