Registers a device to receive push sync notifications.
See https://www.paws-r-sdk.com/docs/cognitosync_register_device/ for full documentation.
cognitosync_register_device(IdentityPoolId, IdentityId, Platform, Token)
[required] A name-spaced GUID (for example, us-east-1:23EC4050-6AEA-7089-A2DD-08002EXAMPLE) created by Amazon Cognito. Here, the ID of the pool that the identity belongs to.
[required] The unique ID for this identity.
[required] The SNS platform type (e.g. GCM, SDM, APNS, APNS_SANDBOX).
[required] The push token.