diff --git a/src/actor/actor_cell.rs b/src/actor/actor_cell.rs
index 8ee860e6..ff541beb 100644
--- a/src/actor/actor_cell.rs
+++ b/src/actor/actor_cell.rs
@@ -17,7 +17,7 @@ use crate::{
     actor::{props::ActorFactory, *},
     kernel::{
         kernel_ref::{dispatch, dispatch_any, KernelRef},
-        mailbox::{AnySender, MailboxSender},
+        mailbox::{AnyEnqueueError, AnySender, MailboxSender},
     },
     system::{
         timer::{Job, OnceJob, RepeatJob, ScheduleId, Timer},
@@ -124,7 +124,7 @@ impl ActorCell {
         &self,
         msg: &mut AnyMessage,
         sender: crate::actor::Sender,
-    ) -> Result<(), ()> {
+    ) -> Result<(), AnyEnqueueError> {
         let mb = &self.inner.mailbox;
         let k = self.kernel();
 
@@ -603,7 +603,7 @@ where
         T: Message + Into<M>,
         M: Message,
     {
-        let delay = std::cmp::max(time.timestamp() - Utc::now().timestamp(), 0 as i64);
+        let delay = std::cmp::max(time.timestamp() - Utc::now().timestamp(), 0_i64);
         let delay = Duration::from_secs(delay as u64);
 
         let id = Uuid::new_v4();
diff --git a/src/actor/actor_ref.rs b/src/actor/actor_ref.rs
index cc6df092..1123910a 100644
--- a/src/actor/actor_ref.rs
+++ b/src/actor/actor_ref.rs
@@ -6,6 +6,7 @@ use crate::{
         props::{ActorArgs, ActorFactory, ActorFactoryArgs},
         Actor, ActorPath, ActorUri, BoxActorProd, CreateError,
     },
+    kernel::mailbox::AnyEnqueueError,
     system::{ActorSystem, SystemMsg},
     AnyMessage, Envelope, Message,
 };
@@ -192,7 +193,7 @@ impl BasicActorRef {
         &self,
         msg: Msg,
         sender: impl Into<Option<BasicActorRef>>,
-    ) -> Result<(), ()>
+    ) -> Result<(), AnyEnqueueError>
     where
         Msg: Message + Send,
     {
@@ -203,7 +204,7 @@ impl BasicActorRef {
         &self,
         msg: &mut AnyMessage,
         sender: impl Into<Option<BasicActorRef>>,
-    ) -> Result<(), ()> {
+    ) -> Result<(), AnyEnqueueError> {
         self.cell.send_any_msg(msg, sender.into())
     }
 }
diff --git a/src/kernel/kernel_ref.rs b/src/kernel/kernel_ref.rs
index cf4e36bd..6c235c46 100644
--- a/src/kernel/kernel_ref.rs
+++ b/src/kernel/kernel_ref.rs
@@ -5,7 +5,7 @@ use futures::{channel::mpsc::Sender, task::SpawnExt, SinkExt};
 use crate::{
     actor::{MsgError, MsgResult},
     kernel::{
-        mailbox::{AnySender, MailboxSchedule, MailboxSender},
+        mailbox::{AnyEnqueueError, AnySender, MailboxSchedule, MailboxSender},
         KernelMsg,
     },
     system::ActorSystem,
@@ -72,18 +72,13 @@ pub fn dispatch_any(
     mbox: &Arc<dyn AnySender>,
     kernel: &KernelRef,
     sys: &ActorSystem,
-) -> Result<(), ()> {
-    match mbox.try_any_enqueue(msg, sender) {
-        Ok(_) => {
-            if !mbox.is_sched() {
-                mbox.set_sched(true);
-                kernel.schedule(sys);
-            }
-
-            Ok(())
+) -> Result<(), AnyEnqueueError> {
+    mbox.try_any_enqueue(msg, sender).map(|_| {
+        if !mbox.is_sched() {
+            mbox.set_sched(true);
+            kernel.schedule(sys);
         }
-        Err(_) => Err(()),
-    }
+    })
 }
 
 unsafe impl Send for KernelRef {}
diff --git a/src/kernel/mailbox.rs b/src/kernel/mailbox.rs
index 6a6f3cbd..eee60cc3 100644
--- a/src/kernel/mailbox.rs
+++ b/src/kernel/mailbox.rs
@@ -24,8 +24,17 @@ pub trait MailboxSchedule {
     fn is_scheduled(&self) -> bool;
 }
 
+#[derive(Debug)]
+pub struct AnyEnqueueError;
+
+impl From<()> for AnyEnqueueError {
+    fn from(_: ()) -> AnyEnqueueError {
+        AnyEnqueueError
+    }
+}
+
 pub trait AnySender: Send + Sync {
-    fn try_any_enqueue(&self, msg: &mut AnyMessage, sender: Sender) -> Result<(), ()>;
+    fn try_any_enqueue(&self, msg: &mut AnyMessage, sender: Sender) -> Result<(), AnyEnqueueError>;
 
     fn set_sched(&self, b: bool);
 
@@ -64,13 +73,13 @@ impl<Msg> AnySender for MailboxSender<Msg>
 where
     Msg: Message,
 {
-    fn try_any_enqueue(&self, msg: &mut AnyMessage, sender: Sender) -> Result<(), ()> {
-        let actual = msg.take()?;
+    fn try_any_enqueue(&self, msg: &mut AnyMessage, sender: Sender) -> Result<(), AnyEnqueueError> {
+        let actual = msg.take().map_err(|_| AnyEnqueueError)?;
         let msg = Envelope {
             msg: actual,
             sender,
         };
-        self.try_enqueue(msg).map_err(|_| ())
+        self.try_enqueue(msg).map_err(|_| AnyEnqueueError)
     }
 
     fn set_sched(&self, b: bool) {
diff --git a/src/lib.rs b/src/lib.rs
index 413c3cab..b3a81be1 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -64,6 +64,8 @@ pub struct AnyMessage {
     pub msg: Option<Box<dyn Any + Send>>,
 }
 
+pub struct DowncastAnyMessageError;
+
 impl AnyMessage {
     pub fn new<T>(msg: T, one_time: bool) -> Self
     where
@@ -75,7 +77,7 @@ impl AnyMessage {
         }
     }
 
-    pub fn take<T>(&mut self) -> Result<T, ()>
+    pub fn take<T>(&mut self) -> Result<T, DowncastAnyMessageError>
     where
         T: Any + Message,
     {
@@ -85,16 +87,16 @@ impl AnyMessage {
                     if m.is::<T>() {
                         Ok(*m.downcast::<T>().unwrap())
                     } else {
-                        Err(())
+                        Err(DowncastAnyMessageError)
                     }
                 }
-                None => Err(()),
+                None => Err(DowncastAnyMessageError),
             }
         } else {
             match self.msg.as_ref() {
                 Some(m) if m.is::<T>() => Ok(m.downcast_ref::<T>().cloned().unwrap()),
-                Some(_) => Err(()),
-                None => Err(()),
+                Some(_) => Err(DowncastAnyMessageError),
+                None => Err(DowncastAnyMessageError),
             }
         }
     }
diff --git a/src/system.rs b/src/system.rs
index a707875e..72e9a060 100644
--- a/src/system.rs
+++ b/src/system.rs
@@ -760,7 +760,7 @@ impl Timer for ActorSystem {
         T: Message + Into<M>,
         M: Message,
     {
-        let delay = std::cmp::max(time.timestamp() - Utc::now().timestamp(), 0 as i64);
+        let delay = std::cmp::max(time.timestamp() - Utc::now().timestamp(), 0_i64);
         let delay = Duration::from_secs(delay as u64);
 
         let id = Uuid::new_v4();