Prioritization of outgoing streams

[PaulRBerg]

Problem

@IaroslavMazur pointed out a problem in a comment buried on Notion (on February 3):

If we interconnect all of the Streams (both incoming and outgoing) for an address, the user controlling that address won’t be able to do the following:

• let an outgoing Stream “die out” naturally by consuming all of the associated assets and being closed by the SabVM cron job. Instead, the user will have to close every Stream by hand;
• prioritize the outgoing Streams (via explicit deposits into them) based on their importance (all of the outgoing Streams would have to receive equal treatment).

A real-life example: as a business manager, you’re allocating resources towards your employees’ salaries, business infrastructure costs, cleaning services, fresh daily fruits and weekly massage for the employees. If your revenues (i.e. “incoming Streams”) start going down, you don’t wait until you can’t afford anything of the above, but start with cutting down the less-vital spendings (like, the massage).

In TradFi, it’s possible to control how exactly your revenues are being spent, and I think that we should also allow this in SabVM.

In other words, SabVM users should be able to specify the order in which their outgoing streams will be knocked out.

The default and (so far implied) order has been "first come, first served", i.e., older streams are closed first. However, I agree with @IaroslavMazur that would lead to a bad UX.

Solution

More research needed, but I conjecture that we will need to do something like this:

1. Opcode for reprioritizing recipients
2. Add an order field to each stream

I suggest deferring this feature for Odyssey.

Feedback

CC @sablier-labs/sabvm