fails:IO.binwrite coerces the argument to a string using to_s
fails:IO.binwrite returns the number of bytes written
fails:IO.binwrite creates a file if missing
fails:IO.binwrite creates file if missing even if offset given
fails:IO.binwrite truncates the file and writes the given string
fails:IO.binwrite doesn't truncate the file and writes the given string if an offset is given
fails:IO.binwrite doesn't truncate and writes at the given offset after passing empty opts
fails:IO.binwrite accepts a :mode option
fails:IO.binwrite raises an error if readonly mode is specified
fails:IO.binwrite truncates if empty :opts provided and offset skipped
fails:IO.binwrite needs to be reviewed for spec completeness
