Prevent players from swimming up waterfalls

[mworzala]

We need to determine if this is possible to do while still maintaining a good user experience. The ask is to prevent players from climbing a waterfall because there is desire to put a cave + parkour challenge there, but swimming up the waterfall defeats the purpose of the parkour.

There were two methods to do this surfaced:

• Give the player a negative velocity while inside downwards flowing water enough that they cannot swim up
• Negative velocity + 3 hunger to prevent swimming. This can be accomplished in vanilla with a bubble column.
  • Potentially instead of setting 3 hunger we can prevent swimming some other way