bufferedByLine is a performance enhancement over std.stdio.File.byLine. It works by reading a large buffer from the input stream rather than just a single line.
The file argument needs to be a File object open for reading, typically a filesystem file or standard input. Use the Yes.keepTerminator template parameter to keep the newline. This is similar to stdio.File.byLine, except specified as a template paramter rather than a runtime parameter.
Reading in blocks does mean that input is not read until a full buffer is available or end-of-file is reached. For this reason, bufferedByLine is not appropriate for interactive input.