feat(socketioxide): properly send binary payloads embedded in structs

In order to reduce possible API-use confusion, ConfOperators and
BroadcastOperators now has a new type param, for a new (sealed) trait,
BinaryHolding, which "tells" the struct whether or not the user has
added binary data or not.

If the user has not added binary data, the operator will be
WithoutBinary, and emit() and emit_with_ack() take a T: Serialize as
usual, and those methods will attempt to extract any binary payloads
from the user-provided struct before sending the event.

If the user explicitly adds binary data (by calling the bin() method),
they will get back a new instance of the operator that is WithBinary.
Then the emit() and emit_with_ack() methods will take a
serde_json::Value, which is expected to already have placeholder objects
where any binary payload is supposed to be.

e2e/socketioxide/socketioxide.rs

@@ -39,7 +39,7 @@ fn on_connect(socket: SocketRef, Data(data): Data<Value>) {
         |s: SocketRef, Data::<Value>(data), Bin(bin)| async move {
             let ack = s
                 .bin(bin)
-                .emit_with_ack::<_, Value>("emit-with-ack", data)
+                .emit_with_ack::<Value>("emit-with-ack", data)
                 .unwrap()
                 .await
                 .unwrap();

socketioxide/src/io.rs

@@ -15,7 +15,10 @@ use crate::{
     extract::SocketRef,
     handler::ConnectHandler,
     layer::SocketIoLayer,
-    operators::{BroadcastOperators, RoomParam},
+    operators::{
+        holding::{WithBinary, WithoutBinary},
+        BroadcastOperators, RoomParam,
+    },
     service::SocketIoService,
     BroadcastError, DisconnectError,
 };
@@ -375,7 +378,7 @@ impl<A: Adapter> SocketIo<A> {
     ///    println!("found socket on /custom_ns namespace with id: {}", socket.id);
     /// }
     #[inline]
-    pub fn of<'a>(&self, path: impl Into<&'a str>) -> Option<BroadcastOperators<A>> {
+    pub fn of<'a>(&self, path: impl Into<&'a str>) -> Option<BroadcastOperators<WithoutBinary, A>> {
         self.get_op(path.into())
     }
 
@@ -401,7 +404,7 @@ impl<A: Adapter> SocketIo<A> {
     ///   println!("found socket on / ns in room1 with id: {}", socket.id);
     /// }
     #[inline]
-    pub fn to(&self, rooms: impl RoomParam) -> BroadcastOperators<A> {
+    pub fn to(&self, rooms: impl RoomParam) -> BroadcastOperators<WithoutBinary, A> {
         self.get_default_op().to(rooms)
     }
 
@@ -429,7 +432,7 @@ impl<A: Adapter> SocketIo<A> {
     ///   println!("found socket on / ns in room1 with id: {}", socket.id);
     /// }
     #[inline]
-    pub fn within(&self, rooms: impl RoomParam) -> BroadcastOperators<A> {
+    pub fn within(&self, rooms: impl RoomParam) -> BroadcastOperators<WithoutBinary, A> {
         self.get_default_op().within(rooms)
     }
 
@@ -462,7 +465,7 @@ impl<A: Adapter> SocketIo<A> {
     ///   println!("found socket on / ns in room1 with id: {}", socket.id);
     /// }
     #[inline]
-    pub fn except(&self, rooms: impl RoomParam) -> BroadcastOperators<A> {
+    pub fn except(&self, rooms: impl RoomParam) -> BroadcastOperators<WithoutBinary, A> {
         self.get_default_op().except(rooms)
     }
 
@@ -489,7 +492,7 @@ impl<A: Adapter> SocketIo<A> {
     ///   println!("found socket on / ns in room1 with id: {}", socket.id);
     /// }
     #[inline]
-    pub fn local(&self) -> BroadcastOperators<A> {
+    pub fn local(&self) -> BroadcastOperators<WithoutBinary, A> {
         self.get_default_op().local()
     }
 
@@ -532,7 +535,7 @@ impl<A: Adapter> SocketIo<A> {
     ///      }
     ///   });
     #[inline]
-    pub fn timeout(&self, timeout: Duration) -> BroadcastOperators<A> {
+    pub fn timeout(&self, timeout: Duration) -> BroadcastOperators<WithoutBinary, A> {
         self.get_default_op().timeout(timeout)
     }
 
@@ -559,9 +562,12 @@ impl<A: Adapter> SocketIo<A> {
     ///   .to("room3")
     ///   .except("room2")
     ///   .bin(vec![Bytes::from_static(&[1, 2, 3, 4])])
-    ///   .emit("test", ());
+    ///   .emit("test", ().into());
     #[inline]
-    pub fn bin(&self, binary: impl IntoIterator<Item = impl Into<Bytes>>) -> BroadcastOperators<A> {
+    pub fn bin(
+        &self,
+        binary: impl IntoIterator<Item = impl Into<Bytes>>,
+    ) -> BroadcastOperators<WithBinary, A> {
         self.get_default_op().bin(binary)
     }
 
@@ -787,7 +793,7 @@ impl<A: Adapter> SocketIo<A> {
 
     /// Returns a new operator on the given namespace
     #[inline(always)]
-    fn get_op(&self, path: &str) -> Option<BroadcastOperators<A>> {
+    fn get_op(&self, path: &str) -> Option<BroadcastOperators<WithoutBinary, A>> {
         self.0
             .get_ns(path)
             .map(|ns| BroadcastOperators::new(ns).broadcast())
@@ -799,7 +805,7 @@ impl<A: Adapter> SocketIo<A> {
     ///
     /// If the **default namespace "/" is not found** this fn will panic!
     #[inline(always)]
-    fn get_default_op(&self) -> BroadcastOperators<A> {
+    fn get_default_op(&self) -> BroadcastOperators<WithoutBinary, A> {
         self.get_op("/").expect("default namespace not found")
     }
 }