pub fn close(
  file_handle: WritableFileStream,
) -> Promise(Result(Nil, String))

pub fn create_writable(
  file_handle: FileHandle,
) -> Promise(Result(WritableFileStream, String))

pub fn get_file(
  file_handle: FileHandle,
) -> Promise(Result(File, String))

pub fn show_directory_picker() -> Promise(
  Result(DirectoryHandle, String),
)

pub fn show_open_file_picker() -> Promise(
  Result(Array(FileHandle), String),
)

pub fn show_save_file_picker() -> Promise(
  Result(FileHandle, String),
)

pub fn write(
  file_handle: WritableFileStream,
  content: BitArray,
) -> Promise(Result(Nil, String))