diff --git a/Cargo.toml b/Cargo.toml
index 5ec3276..17b89af 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -7,3 +7,11 @@ edition = "2018"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+
+[dependencies.tokio]
+version = "1"
+features = ["sync"]
+
+[dev-dependencies.tokio]
+version = "1"
+features = ["rt", "macros"]
diff --git a/src/lib.rs b/src/lib.rs
index b975326..5083abf 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -4,6 +4,14 @@ pub trait Message: 'static + Clone + Send + Sync {}
 
 impl<T> Message for T where T: 'static + Clone + Send + Sync {}
 
+#[derive(Clone, Debug, PartialEq)]
+#[non_exhaustive]
+pub enum SubscribeError {}
+
+#[derive(Clone, Debug, PartialEq)]
+#[non_exhaustive]
+pub enum AdvertiseError {}
+
 pub struct Orsb {}
 
 impl Orsb {
@@ -11,18 +19,26 @@ impl Orsb {
         todo!()
     }
 
-    pub fn subscribe<T: Message>(&mut self) -> Subscription<T> {
+    pub async fn subscribe<T: Message>(&mut self) -> Result<Subscription<T>, SubscribeError> {
         todo!()
     }
 
-    pub fn advertise<T: Message>(&mut self) -> Publication<T> {
+    pub async fn advertise<T: Message>(&mut self) -> Result<Publication<T>, AdvertiseError> {
+        todo!()
+    }
+
+    pub fn subscribe_blocking<T: Message>(&mut self) -> Result<Subscription<T>, SubscribeError> {
+        todo!()
+    }
+
+    pub fn advertise_blocking<T: Message>(&mut self) -> Result<Publication<T>, AdvertiseError> {
         todo!()
     }
 }
 
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, PartialEq)]
 #[non_exhaustive]
-pub enum RecvErr {
+pub enum RecvError {
     Empty,
     Closed,
     Lagged,
@@ -33,22 +49,22 @@ pub struct Subscription<T> {
 }
 
 impl<T: Message> Subscription<T> {
-    pub async fn recv_wait(&mut self) -> Result<T, RecvErr> {
+    pub async fn recv(&mut self) -> Result<T, RecvError> {
         todo!()
     }
 
-    pub fn recv(&mut self) -> Result<T, RecvErr> {
+    pub fn recv_blocking(&mut self) -> Result<T, RecvError> {
         todo!()
     }
 
-    pub fn try_recv(&mut self) -> Result<T, RecvErr> {
+    pub fn try_recv(&mut self) -> Result<T, RecvError> {
         todo!()
     }
 }
 
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, PartialEq)]
 #[non_exhaustive]
-pub enum SendErr {
+pub enum SendError {
     NoListeners,
 }
 
@@ -57,7 +73,33 @@ pub struct Publication<T> {
 }
 
 impl<T: Message> Publication<T> {
-    pub fn send(&mut self) -> Result<T, SendErr> {
+    pub fn send(&mut self, message: T) -> Result<(), SendError> {
+        let _ = message;
         todo!()
     }
 }
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[derive(Clone, Debug, PartialEq)]
+    struct TestMsg(u8);
+
+    #[test]
+    fn test_sync() {
+        let mut orsb = Orsb::new();
+
+        let mut sub = orsb.subscribe_blocking::<TestMsg>().unwrap();
+        let mut publ = orsb.advertise_blocking::<TestMsg>().unwrap();
+
+        publ.send(TestMsg(10)).unwrap();
+        publ.send(TestMsg(20)).unwrap();
+        publ.send(TestMsg(30)).unwrap();
+
+        assert_eq!(sub.recv_blocking(), Ok(TestMsg(10)));
+        assert_eq!(sub.recv_blocking(), Ok(TestMsg(20)));
+        assert_eq!(sub.recv_blocking(), Ok(TestMsg(30)));
+        assert_eq!(sub.try_recv(), Err(RecvError::Empty));
+    }
+}