Added stub for chunk(py 2 and 3) (#1523)

stdlib/2and3/chunk.pyi

@@ -0,0 +1,23 @@
+# Source(py2): https://hg.python.org/cpython/file/2.7/Lib/chunk.py
+# Source(py3): https://github.com/python/cpython/blob/master/Lib/chunk.py
+
+from typing import IO
+
+class Chunk:
+    closed = ...  # type: bool
+    align = ...  # type: bool
+    file = ...  # type: IO[bytes]
+    chunkname = ...  # type: bytes
+    chunksize = ...  # type: int
+    size_read = ...  # type: int
+    offset = ...  # type: int
+    seekable = ...  # type: bool
+    def __init__(self, file: IO[bytes], align: bool = ..., bigendian: bool = ..., inclheader: bool = ...) -> None: ...
+    def getname(self) -> bytes: ...
+    def getsize(self) -> int: ...
+    def close(self) -> None: ...
+    def isatty(self) -> bool: ...
+    def seek(self, pos: int, whence: int = ...) -> None: ...
+    def tell(self) -> int: ...
+    def read(self, size: int = ...) -> bytes: ...
+    def skip(self) -> None: ...