Resolve service dependencies.

Kahn's algorithm.

Stderr represents standard error stream type.

Stdin represents standard input stream type.

Stdout represents standard output stream type.

JSONError wraps a concrete Code and Message, `Code` is a integer error code, `Message` is the error message.

JSONMessage defines a message struct.

JSONProgress describes a Progress.

StatusError reports an unsuccessful exit by a command.

StdType is the type of standard stream a writer can multiplex to.