pub trait SysBlocks {
// Required methods
fn read_dir(&mut self) -> ReadDir;
fn read_env(&mut self) -> ReadEnv;
fn read_file(&mut self) -> ReadFile;
fn read_stdin(&mut self) -> ReadStdin;
fn write_file(&mut self) -> WriteFile;
fn write_stderr(&mut self) -> WriteStderr;
fn write_stdout(&mut self) -> WriteStdout;
}