Whether this object's path is absolute.
An absolute path is independent of the current working directory (Directory.current). A non-absolute path must be interpreted relative to the current working directory.
On Windows, a path is absolute if it starts with
(two backslashes or representing a UNC path) or with a drive letter
z (upper or lower case) followed by
This makes, for example,
\file.ext a non-absolute path
because it depends on the current drive letter.
On non-Windows, a path is absolute if it starts with
If the path is not absolute, use absolute to get an entity with an absolute path referencing the same object in the file system, if possible.
bool get isAbsolute => _isAbsolute(path);