The job is hanging (writing out bad_rows but not good rows, and the problem is something
introduced in the float processing code added yesterday (commits:

b8e4eb2867872dd210c6ee4eefc4be0f2d5c58a6 or d65ccccdb3626a7ab3e2c5ce571e1b24264389d6

)

Hypothesis: the problem is trying to use Scala Floats rather than Java Floats.

Therefore I have updated the code to use JFloats, and I've also changed references to Ints to JIntegers, to remove ambiguity.

We'll see if this works.