Create a standard tus client model

[Acconut]

• Create a state machine model for tus uploads
• Use https://github.com/pfusik/cito to build core logic for tus client
• Add JS implementations around core logic to complete tus client

[Acconut]

First attempt at a state transition chart:

• Rounded boxes are states
• Circles show the invocation of public methods (from library user) or private methods (from client itself)

[Acconut]

Public interface for controlling uploads:

• createUpload
• resumeUpload
• createOrResumeUpload
• pauseUpload

[koppor]

Maybe, XState helps here? Checking their tutorial and that they can invoke services, I thought, it could be a good thing to use?

[Acconut]

XState is a promising library for JavaScript, thanks for sharing! This issue is also intended to look into ways how we can build state machines that are shared across different programming languages. That could allow reusing the state machines in our JavaScript, Python, Swift and Java clients without the need of re-implementing the same logic everywhere. However, I haven't spent enough time on it yet to see if such a tooling already exists.