Emits a http_request_done internal notification.

With networking enabled, CDP listens to this event and emits a
`Network.loadingFinished` event. This is event is used by puppeteer to know that
details about the response (i.e. the body) can be queries.

Added dummy handling for the Network.getResponseBody message. Returns an
empty body. Needed because we emit the loadingFinished event which signals
to drivers that they can ask for the body.

src/notification.zig

@@ -64,6 +64,7 @@ pub const Notification = struct {
         http_request_start: List = .{},
         http_request_intercept: List = .{},
         http_headers_done: List = .{},
+        http_request_done: List = .{},
         notification_created: List = .{},
     };
 
@@ -76,6 +77,7 @@ pub const Notification = struct {
         http_request_start: *const RequestStart,
         http_request_intercept: *const RequestIntercept,
         http_headers_done: *const ResponseHeadersDone,
+        http_request_done: *const RequestDone,
         notification_created: *Notification,
     };
     const EventType = std.meta.FieldEnum(Events);
@@ -106,6 +108,10 @@ pub const Notification = struct {
         transfer: *Transfer,
     };
 
+    pub const RequestDone = struct {
+        transfer: *Transfer,
+    };
+
     pub const RequestFail = struct {
         transfer: *Transfer,
         err: anyerror,