fast: Fix configurable saveToken and fetchToken

packages/client-core/src/fast/fast.js

@@ -21,16 +21,18 @@ export default function fast({ sasl2 }, { saveToken, fetchToken } = {}) {
   Object.assign(fast, {
     mechanism: null,
     mechanisms: [],
-    async saveToken() {
+    saveToken,
+    fetchToken,
+    async save(token) {
       try {
-        await saveToken();
+        await this.saveToken(token);
       } catch (err) {
         fast.emit("error", err);
       }
     },
-    async fetchToken() {
+    async fetch() {
       try {
-        return await fetchToken();
+        return await this.fetchToken();
       } catch (err) {
         fast.emit("error", err);
       }
@@ -107,17 +109,13 @@ export default function fast({ sasl2 }, { saveToken, fetchToken } = {}) {
     },
     async (element) => {
       if (element.is("token", NS)) {
-        try {
-          await saveToken({
-            // The token is bound by the mechanism
-            // > Servers MUST bind tokens to the mechanism selected by the client in its original request, and reject attempts to use them with other mechanisms.
-            mechanism: fast.mechanism,
-            token: element.attrs.token,
-            expiry: element.attrs.expiry,
-          });
-        } catch (err) {
-          fast.emit("error", err);
-        }
+        await fast.save({
+          // The token is bound by the mechanism
+          // > Servers MUST bind tokens to the mechanism selected by the client in its original request, and reject attempts to use them with other mechanisms.
+          mechanism: fast.mechanism,
+          token: element.attrs.token,
+          expiry: element.attrs.expiry,
+        });
       }
     },
   );

packages/client/lib/createOnAuthenticate.js

@@ -16,7 +16,7 @@ export default function createOnAuthenticate(credentials, userAgent) {
       return;
     }
 
-    credentials.token = await fast?.fetchToken?.();
+    credentials.token = await fast?.fetch?.();
 
     await authenticate(credentials, mechanisms[0], userAgent);
   };