Add _TemporaryFileWrapper (#4559)

stdlib/3/tempfile.pyi

@@ -164,6 +164,39 @@ else:
             dir: Optional[_DirT[AnyStr]] = ...,
         ) -> IO[Any]: ...
 
+class _TemporaryFileWrapper(IO[str]):
+    file: IO[str]
+    name: Any
+    delete: bool
+    def __init__(self, file: IO[str], name: Any, delete: bool = ...) -> None: ...
+    def __enter__(self) -> _TemporaryFileWrapper: ...
+    def __exit__(
+        self, exc: Optional[Type[BaseException]], value: Optional[BaseException], tb: Optional[TracebackType]
+    ) -> Optional[bool]: ...
+    def __getattr__(self, name: str) -> Any: ...
+    def close(self) -> None: ...
+    def unlink(self, path: str) -> None: ...
+    # These methods don't exist directly on this object, but
+    # are delegated to the underlying IO object through __getattr__.
+    # We need to add them here so that this class is concrete.
+    def __iter__(self) -> Iterator[str]: ...
+    def __next__(self) -> str: ...
+    def fileno(self) -> int: ...
+    def flush(self) -> None: ...
+    def isatty(self) -> bool: ...
+    def next(self) -> str: ...
+    def read(self, n: int = ...) -> str: ...
+    def readable(self) -> bool: ...
+    def readline(self, limit: int = ...) -> str: ...
+    def readlines(self, hint: int = ...) -> List[str]: ...
+    def seek(self, offset: int, whence: int = ...) -> int: ...
+    def seekable(self) -> bool: ...
+    def tell(self) -> int: ...
+    def truncate(self, size: Optional[int] = ...) -> int: ...
+    def writable(self) -> bool: ...
+    def write(self, s: str) -> int: ...
+    def writelines(self, lines: Iterable[str]) -> None: ...
+
 # It does not actually derive from IO[AnyStr], but it does implement the
 # protocol.
 class SpooledTemporaryFile(IO[AnyStr]):