See if the directory exists. If there's an error checking if the directory exists, this method throws an
exception when possible, though for some platform implementations it'll just return false if platform can't
distinguish not existing from there being an error checking.
Rename this directory, giving it a new name in the same parent directory. If a directory with the specified name
already exists, an exception is thrown. If/when there's the need to move a Directory to a different directory,
we'll add separate support for that.
Visit the child elements of this path--basically list the files and subdirectories of a directory, calling the
visitor for each. Just direct children are listed, not all descendants; callers can call this method recursively
if they want to visit all descendants. If the path isn't a directory, an exception is thrown.
Set the last modified time for the directory, if supported by the platform (that is, if
isSetLastModifiedTimeSupported() returns true). If not supported by the platform, this method does nothing. If
supported by the platform but an error occurs when changing the last modified time (e.g. the caller doesn't have
rights to change it), then this method throws an exception.