[Suggestion] Make loaders input always lane-balanced

[AndyScull]

Hello!
Just noticed weird behavior with loaders - if I use a loader-chest-unloader as a buffer and consumption down the line prefers one lane then the first loader loads only from left lane
Some small test in creative mode -

On the right you can turn on/off lane consumption by rotating loaders into trash chests, if only one of them is active then the whole system only consumes left lane from output chest on the left
Blueprint string:
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

Just to be sure I tested that this happens specifically with 5dim transport mod -

1. Created new sandbox game with all mods disabled
2. Made same test blueprint with vanilla loaders, they did load from both lanes
3. Enabled 5dim core, transport, and bob inserters mods and loaded the sandbox
4. Vanilla loaders got replaced with modded ones, and they now consume left lane only

[AndyScull]

Some thoughts:
I don't actually know why but I can't reproduce the 'proper' behavior with vanilla loaders, which I thought were loading from both lanes always. I must be going senile :(
Anyway the problem is actually non-existent if you want to use loaders for single belt lane balancing (loader->chest->loader).
It doesn't work if you limit chest slots or use it to fill up to max, but it works as a lane balancer if you limit chest with circuit instead of limiting slots. Connect a circuit line from belt before to chest and make the belt work only if chest contains less than X items.
From my understanding of situation - imagine your buffer chest is full, only one lane is actively consumed after the buffer. One item at a time goes out through output loader, one item goes in since there's only enough space in chest for 1. So that means input loader would only load 1 item per cycle, consuming only single lane in the end.
With circuit stopping the belt before loading, it loads 'in bulk' all the items that are on that belt segment. So effectively it loads equally from both input lanes