Remove unused utility function consume()

Unused since e706af20fe.

src/pip/_internal/utils/misc.py

@@ -14,7 +14,6 @@ import shutil
 import stat
 import sys
 import urllib.parse
-from collections import deque
 from io import StringIO
 from itertools import filterfalse, tee, zip_longest
 
@@ -635,11 +634,6 @@ def get_installed_version(dist_name, working_set=None):
     return dist.version if dist else None
 
 
-def consume(iterator):
-    """Consume an iterable at C speed."""
-    deque(iterator, maxlen=0)
-
-
 # Simulates an enum
 def enum(*sequential, **named):
     enums = dict(zip(sequential, range(len(sequential))), **named)