DiscordKit: can receive and decode hello event

Sources/DiscordKit/GatewayClient.swift

@@ -0,0 +1,27 @@
+import Foundation
+#if canImport(FoundationNetowrking)
+import FoundationNetworking
+#endif
+
+struct GatewayClient {
+    let gatewayURL: URL
+
+    func openConnection() async throws {
+        let ws = URLSession.shared.webSocketTask(with: gatewayURL.appending(component: "?v=10&encoding=json"))
+        ws.resume()
+        let message =  try await ws.receive()
+        guard case .string(let str) = message else { throw GatewayError.invalidMessage }
+        print(str)
+        let json = JSONDecoder()
+        let gwMessage = try json.decode(GatewayMessage.self, from: Data(str.utf8))
+        dump(gwMessage)
+        guard case .hello(let hello) = gwMessage.d else { print("whoops"); return }
+        dump(hello)
+    }
+
+}
+
+public enum GatewayError: Error {
+    case invalidMessage
+    case invalidOpcode
+}