Lines returns an iterator over lines in a file. The iterator yields each line without the trailing newline character. If the file cannot be opened, th

MapReduce executes a map-reduce operation with configurable parallelism. Type parameters: - In: the type of input items - Mid: the intermediate type

findFiles returns a channel that yields all file paths under the given directory.

countWords processes a single file and sends word counts to the output channel.

reduce aggregates word counts from all mappers into a final result.