Better handling of unsupported requests.

SecretAgentKit/Agent.swift

@@ -26,7 +26,11 @@ extension Agent {
         let data = reader.availableData
         guard !data.isEmpty else { return }
         let requestTypeInt = data[4]
-        guard let requestType = SSHAgent.RequestType(rawValue: requestTypeInt) else { return }
+        guard let requestType = SSHAgent.RequestType(rawValue: requestTypeInt) else {
+            writer.write(SSHAgent.ResponseType.agentFailure.data)
+            os_log(.debug, "Agent returned %@", SSHAgent.ResponseType.agentFailure.debugDescription)
+            return
+        }
         os_log(.debug, "Agent handling request of type %@", requestType.debugDescription)
         let subData = Data(data[5...])
         let response = handle(requestType: requestType, data: subData, reader: reader)

SecretAgentKit/SSHAgentProtocol.swift

@@ -12,7 +12,7 @@ extension SSHAgent {
             switch self {
             case .requestIdentities:
                 return "RequestIdentities"
-            default:
+            case .signRequest:
                 return "SignRequest"
             }
         }