diff --git a/distributed/utils.py b/distributed/utils.py
index afe048c2ac8..64203488d12 100644
--- a/distributed/utils.py
+++ b/distributed/utils.py
@@ -1124,21 +1124,8 @@ def color_of(x, palette=palette):
     return palette[n % len(palette)]
 
 
-def _iscoroutinefunction(f):
-    return inspect.iscoroutinefunction(f) or gen.is_coroutine_function(f)
-
-
-@functools.lru_cache(None)
-def _iscoroutinefunction_cached(f):
-    return _iscoroutinefunction(f)
-
-
 def iscoroutinefunction(f):
-    # Attempt to use lru_cache version and fall back to non-cached version if needed
-    try:
-        return _iscoroutinefunction_cached(f)
-    except TypeError:  # unhashable type
-        return _iscoroutinefunction(f)
+    return inspect.iscoroutinefunction(f) or gen.is_coroutine_function(f)
 
 
 @contextmanager