Hey everyone: I'd like to rename DoFn.Context#sideOutput to #output (in the Java SDK).
Having two methods, both named output, one which takes the "main output type" and one that takes a tag to specify the type more clearly communicates the actual behavior - sideOutput isn't a "special" way to output, it's the same as output(T), just to a specified PCollection. This will help pipeline authors understand the actual behavior of outputting to a tag, and detangle it from "sideInput", which is a special way to receive input. Giving them the same name means that it's not even strange to call output and provide the main output type, which is what we want - it's a more specific way to output, but does not have different restrictions or capabilities. This is also a pretty small change within the SDK - it touches about 20 files, and the changes are pretty automatic. Thanks, Thomas
