I think we should have an explicitly named method for RDD conversions rather than `apply`, but the choice of name here is pretty deliberately bad so that we'll change it. It would be confusing to overload the `apply` method to mean four different things:

1. Convert an `ADAMRecord` to `DecadantRead`
2. Convert a `RichADAMRecord` to `DecadantRead`
3. Convert an `RDD[ADAMRecord]` to `RDD[DecadentRead]`
4. Convert an `RDD[DecadentRead]` to `RDD[ADAMRecord]`

Also, due to JVM type erasure, we can't use the same name for both 3 and 4, since the erased type is simply `RDD`. How about `convert` and `deconvert` for 3 and 4? Still punny, but only mildly so.