Feature request name
No way to get fluid source and flowing fluid blockstates/blocks using methods in ILiquidDefinition(or at least the documentation doesn't describe it).

Feature request description
There are no methods in ILiquidDefinition to get fluid source block(or block definition) and flowing fluid block, although net.minecraftforge.fluids.Fluid provides getBlock() method.

Feature request reason
This is useful for making custom tools for working with fluids and to make some fluid container items to behave like buckets.

Feature request dependencies
This feature requires adding methods to ILiquidDefinition.