create method Null safety
- {bool recursive: false}
Create the file. Returns a Future<File> that completes with
the file when it has been created.
If recursive is false, the default, the file is created only if
all directories in the path exist. If recursive is true, all
non-existing path components are created.
Existing files are left untouched by create. Calling create on an existing file might fail if there are restrictive permissions on the file.
Completes the future with a FileSystemException if the operation fails.
Implementation
Future<File> create({bool recursive: false});