com.twitter.summingbird.planner.DagOptimizer
If the given Id can be replaced with a simpler expression, return Some(expr) else None.
If the given Id can be replaced with a simpler expression, return Some(expr) else None.
If it is convenient, you might write a partial function and then call .lift to get the correct Function type
Combine flatMaps followed by optionMap into a single operation
On the other direction, you might not want to run optionMap with flatMap since some platforms (storm) can't easily control source parallelism, so we don't want to push big expansions up to sources