Fix no_std build

Signed-off-by: John Nunley <dev@notgull.net>

src/no_std.rs

@@ -240,11 +240,10 @@ impl<T> List<T> {
             queue: concurrent_queue::ConcurrentQueue::unbounded(),
         }
     }
-    pub fn total_listeners(&self) -> Result<usize, &str> {
-        self.inner
-            .try_lock()
-            .map(|lock| Ok(lock.listeners.len()))
-            .unwrap_or(Err("<locked>"))
+
+    /// Try to get the total number of listeners without blocking.
+    pub(super) fn try_total_listeners(&self) -> Option<usize> {
+        self.inner.try_lock().map(|lock| lock.listeners.len())
     }
 }
 

src/std.rs

@@ -46,7 +46,7 @@ impl<T> List<T> {
     }
 
     /// Get the total number of listeners without blocking.
-    pub fn try_total_listeners(&self) -> Option<usize> {
+    pub(crate) fn try_total_listeners(&self) -> Option<usize> {
         self.0.try_lock().ok().map(|list| list.len)
     }