Upload is limited to 5-6 MB/s event when connection can handle more

[stan7123]

When sending an image I cannot do it faster than 5-6MB/s while the internet connection is capable to upload at ~20MB/s.

When running 4 uploading processes - Running at full connection speed:

When running only one uploading process - Running at 5-6MB/s:

[stan7123]

Using more upload workers helps (in my case: --upload-workers 16).