question

https://docs.microsoft.com/en-us/gaming/playfab/features/data/entities/quickstart

void OnInitFileUpload(PlayFab.DataModels.InitiateFileUploadsResponse response)
{
        string payloadStr;
        if (!_entityFileJson.TryGetValue(ActiveUploadFileName, out payloadStr))
            payloadStr = "{}";
        var payload = Encoding.UTF8.GetBytes(payloadStr);

        GlobalFileLock += 1; // Start SimplePutCall
        PlayFabHttp.SimplePutCall(response.UploadDetails[0].UploadUrl,
            payload,
            FinalizeUpload,
            error => { Debug.Log(error); }
        );
        GlobalFileLock -= 1; // Finish InitiateFileUploads
}

void FinalizeUpload(byte[] data)
{
        GlobalFileLock += 1; // Start FinalizeFileUploads
        var request = new PlayFab.DataModels.FinalizeFileUploadsRequest
        {
            Entity = new PlayFab.DataModels.EntityKey { Id = entityId, Type = entityType },
            FileNames = new List<string> { ActiveUploadFileName },
        };
        PlayFabDataAPI.FinalizeFileUploads(request, OnUploadSuccess, OnSharedFailure);
        GlobalFileLock -= 1; // Finish SimplePutCall
}

I don't know how to upload a text file. Is "var payload" the text file that I want to upload?

What exactly is (byte[] data)? Is (byte[] data) the same as "var payload"?

For example, can I use FinalizeUpload(byte[] data) like this to upload a text file?

string assetPath = "/Users/myname/TESTFOLDER/MyFile.txt";
byte[] payload = File.ReadAllBytes(assetPath);
//call a PUT method and upload payload
FinalizeUpload(payload);