Set self._buffer to None

Author: emmatyping

Lib/compression/zstd/_zstdfile.py

@@ -61,6 +61,7 @@ def __init__(
         self._fp = None
         self._close_fp = False
         self._mode = _MODE_CLOSED
+        self._buffer = None
 
         if not isinstance(mode, str):
             raise ValueError("mode must be a str")