feat: HTTP(S) agent uses Keep-Alive for API requests

CHANGELOG.md

@@ -6,6 +6,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 
 ## [Unreleased]
+### Changed
+* Keep-Alive is now used by HTTP(S) agent, to reduce latency for subsequent API requests.
 ### Fixed
 * CI: silence npm audit warnings in non-production dependencies due to 
   currently-unresolvable [vulnerability in semver <7.5.2](https://github.com/npm/node-semver/pull/564). 

src/client.ts

@@ -10,9 +10,16 @@ import { URLSearchParams } from 'url';
 import FormData from 'form-data';
 import { IncomingMessage } from 'http';
 import { ProxyConfig } from './types';
+import * as https from 'https';
+import * as http from 'http';
 
 type HttpMethod = 'GET' | 'DELETE' | 'POST';
 
+const axiosInstance = axios.create({
+    httpAgent: new http.Agent({ keepAlive: true }),
+    httpsAgent: new https.Agent({ keepAlive: true }),
+});
+
 /**
  * Options for sending HTTP requests.
  * @private
@@ -219,7 +226,7 @@ export class HttpClient {
         axiosRequestConfig: AxiosRequestConfig,
     ): Promise<{ statusCode: number; content: TContent }> {
         try {
-            const response = await axios.request(axiosRequestConfig);
+            const response = await axiosInstance.request(axiosRequestConfig);
 
             if (axiosRequestConfig.responseType === 'text') {
                 // Workaround for axios-bug: https://github.com/axios/axios/issues/907