Add support for `client-message` events

These events are issued [1] when clients communicate to each other using
`script-message` [2] and `script-message-to` [3] commands.

[1]: https://mpv.io/manual/stable/#command-interface-client-message
[2]: https://mpv.io/manual/stable/#command-interface-script-message
[3]: https://mpv.io/manual/stable/#command-interface-script-message-to

src/ipc.rs

@@ -414,6 +414,19 @@ pub fn listen(instance: &mut Mpv) -> Result<Event, Error> {
 
             try_convert_property(name.as_ref(), id, data)
         }
+        "client-message" => {
+            let args = match e["args"] {
+                Value::Array(ref a) => json_array_to_vec(a)
+                    .iter()
+                    .map(|arg| match arg {
+                        MpvDataType::String(s) => Ok(s.to_owned()),
+                        _ => Err(Error(ErrorCode::JsonContainsUnexptectedType)),
+                    })
+                    .collect::<Result<Vec<_>, _>>(),
+                _ => return Err(Error(ErrorCode::JsonContainsUnexptectedType)),
+            }?;
+            Event::ClientMessage { args }
+        }
         _ => Event::Unimplemented,
     };
     Ok(event)

src/lib.rs

@@ -25,6 +25,7 @@ pub enum Event {
     PlaybackRestart,
     PropertyChange { id: usize, property: Property },
     ChapterChange,
+    ClientMessage { args: Vec<String> },
     Unimplemented,
 }