fix: resolve 30-second connection hang in v6.0.0+ (#408)

Co-authored-by: Claude <noreply@anthropic.com>

Author: scottlovegrove

package-lock.json

@@ -44,6 +44,7 @@
         "emoji-regex": "10.6.0",
         "form-data": "4.0.4",
         "ts-custom-error": "^3.2.0",
+        "undici": "^7.16.0",
         "uuid": "11.1.0",
         "zod": "4.1.12"
     },

package.json

@@ -1,3 +1,4 @@
+import { Agent } from 'undici'
 import type { HttpResponse, RetryConfig, CustomFetch, CustomFetchResponse } from '../types/http'
 import { isNetworkError } from '../types/http'
 
@@ -14,6 +15,15 @@ const DEFAULT_RETRY_CONFIG: RetryConfig = {
     },
 }
 
+/**
+ * HTTP agent with keepAlive disabled to prevent hanging connections
+ * This ensures the process exits immediately after requests complete
+ */
+const httpAgent = new Agent({
+    keepAliveTimeout: 1, // Close connections after 1ms of idle time
+    keepAliveMaxTimeout: 1, // Maximum time to keep connections alive
+})
+
 /**
  * Converts Headers object to a plain object
  */
@@ -113,6 +123,8 @@ export async function fetchWithRetry<T = unknown>(args: {
                 const nativeResponse = await fetch(url, {
                     ...fetchOptions,
                     signal: requestSignal,
+                    // @ts-expect-error - dispatcher is a valid option for Node.js fetch but not in the TS types
+                    dispatcher: httpAgent,
                 })
                 fetchResponse = convertResponseToCustomFetch(nativeResponse)
             }