client: implements send_message

kordophone/src/api/mod.rs

@@ -1,6 +1,6 @@
 use async_trait::async_trait;
 pub use crate::model::{
-    Conversation, Message, ConversationID, MessageID,
+    Conversation, Message, ConversationID, MessageID, OutgoingMessage,
 };
 
 pub mod auth;
@@ -35,6 +35,12 @@ pub trait APIInterface {
         after: Option<MessageID>,
     ) -> Result<Vec<Message>, Self::Error>;
 
+    // (POST) /sendMessage
+    async fn send_message(
+        &mut self, 
+        outgoing_message: OutgoingMessage,
+    ) -> Result<Message, Self::Error>;
+
     // (POST) /authenticate
     async fn authenticate(&mut self, credentials: Credentials) -> Result<JwtToken, Self::Error>;