Amazon S3 + IAM + Cognito

class AwsS3Sync(val activity: Activity): AsyncTask<Any, Any, Any>() {

     override fun doInBackground(vararg params: Any?): Any? { // Initialize the Amazon Cognito credentials provider
        val credentialsProvider =
            CognitoCachingCredentialsProvider(
                activity.applicationContext,  // Application Context
                "identity pool id",  // Identity Pool ID
                Regions.US_EAST_1 // Region enum,

            )
        val s3Client =
            AmazonS3Client(credentialsProvider, Region.getRegion(Regions.US_EAST_1))
        val fileToUpload: File = File(activity.filesDir, "sample.txt")

         val writer = FileWriter(fileToUpload)
         writer.append("Howdy World!")
         writer.close()
        //(Replace "MY-BUCKET" with your S3 bucket name, and "MY-OBJECT-KEY" with whatever you would like to name the file in S3)
        val putRequest = PutObjectRequest(
            "bucket-name",

            "sample15.txt",
            fileToUpload
        )
        val putResponse: PutObjectResult = s3Client.putObject(putRequest)

         //Log.i("AWS", putResponse.)

        val getRequest = GetObjectRequest("bucket-name", "sample15.txt")
        val getResponse: S3Object = s3Client.getObject(getRequest)
        val myObjectBytes: InputStream = getResponse.getObjectContent()
        // Do what you want with the object
        myObjectBytes.close()
        return null
    }
}