Issue description:

The games crashes while loading a save game.

What happens:

When an Exporter in fluid mode is connected to machines from Advanced Rocketry and Actually Addition the game crashes while loading a save game.

What you expected to happen:

Steps to reproduce:

...

Version (Make sure you are on the latest version before reporting):

• Minecraft: 1.10.2
• Forge: 2122
• Refined Storage: 1.2.5

Does this issue occur on a server? [yes/no]

If a (crash)log is relevant for this issue, link it here:

http://pastebin.com/SCfa83rR

I think you should report this issue to the developer of Actually Addition since it's crashing on their side

It crashes with more mods than just Actually Additions. It was just an example.

The only way this can crash is when the passed FluidStack would be null. Will need investigation.

                               FluidStack took = network.extractFluid(stack, toExtract, compare, true);

                               if (took != null) {
                                   int filled = handler.fill(took, false);
                                   took = network.extractFluid(stack, filled, compare, false);
                                   handler.fill(took, true);
                                   break;
                               }

The NPE happens at handler.fill(took, true);.

What I think happens here is: if filled is 0, it'll try and extract 0 fluid of that type which returns null.