Reuse connectionPromise for relay connect.

pool.ts

@@ -26,22 +26,16 @@ export class SimplePool {
 
   async ensureRelay(url: string): Promise<Relay> {
     const nm = normalizeURL(url)
-    const existing = this._conn[nm]
-    if (existing && existing.status === 1) return existing
 
-    if (existing) {
-      await existing.connect()
-      return existing
+    if (!this._conn[nm]) {
+      this._conn[nm] = relayInit(nm, {
+        getTimeout: this.getTimeout * 0.9,
+        listTimeout: this.getTimeout * 0.9
+      })
     }
 
-    const relay = relayInit(nm, {
-      getTimeout: this.getTimeout * 0.9,
-      listTimeout: this.getTimeout * 0.9
-    })
-    this._conn[nm] = relay
-
+    const relay = this._conn[nm]
     await relay.connect()
-
     return relay
   }