Read chunks in Python's default buffer size

I observed minor performance improvements by using this larger chunk
read size.

Python's docs describe `io.DEFAULT_BUFFER_SIZE` as:

> An int containing the default buffer size used by the module’s
> buffered I/O classes. open() uses the file’s blksize ...

The docs on `blksize` say:

> “Preferred” blocksize for efficient file system I/O. Writing to a file
> in smaller chunks may cause an inefficient read-modify-rewrite.

References:

- https://docs.python.org/3/library/io.html#io.DEFAULT_BUFFER_SIZE
- https://docs.python.org/3/library/os.html#os.stat_result.st_blksize

Author: meshy

invoke/runners.py

@@ -1,5 +1,6 @@
 import errno
 import locale
+import io
 import os
 import signal
 import struct
@@ -72,7 +73,7 @@ class Runner:
 
     opts: Dict[str, Any]
     using_pty: bool
-    read_chunk_size = 1000
+    read_chunk_size = io.DEFAULT_BUFFER_SIZE
     input_sleep = 0.01
 
     def __init__(self, context: "Context") -> None: