Add ability to pass global agent options for HttpClient

lib/HttpClient.ts

@@ -121,6 +121,10 @@ export class HttpClient implements ifm.IHttpClient {
     private _ca: string;
     private _cert: string;
     private _key: string;
+    private _httpGlobalAgentOptions: ifm.IHttpGlobalAgentOptions = {
+        keepAlive: false,
+        timeout: 30_000
+    };
 
     constructor(userAgent: string | null | undefined, handlers?: ifm.IRequestHandler[], requestOptions?: ifm.IRequestOptions) {
         this.userAgent = userAgent;
@@ -148,6 +152,10 @@ export class HttpClient implements ifm.IHttpClient {
                 });
             }
 
+            if (requestOptions.globalAgentOptions) {
+                this._httpGlobalAgentOptions = requestOptions.globalAgentOptions;
+            }
+
             this._certConfig = requestOptions.cert;
 
             if (this._certConfig) {
@@ -529,7 +537,11 @@ export class HttpClient implements ifm.IHttpClient {
 
         // if not using private agent and tunnel agent isn't setup then use global agent
         if (!agent) {
-            agent = usingSsl ? https.globalAgent : http.globalAgent;
+            const globalAgentOptions: http.AgentOptions = { 
+                keepAlive: this._httpGlobalAgentOptions.keepAlive,
+                timeout: this._httpGlobalAgentOptions.timeout
+            };
+            agent = usingSsl ? new https.Agent(globalAgentOptions) : new http.Agent(globalAgentOptions);
         }
 
         if (usingSsl && this._ignoreSslError) {

lib/Interfaces.ts

@@ -47,6 +47,7 @@ export interface IRequestOptions {
     ignoreSslError?: boolean;
     proxy?: IProxyConfiguration;
     cert?: ICertConfiguration;
+    globalAgentOptions?: IHttpGlobalAgentOptions;
     allowRedirects?: boolean;
     allowRedirectDowngrade?: boolean;
     maxRedirects?: number;
@@ -72,6 +73,11 @@ export interface ICertConfiguration {
     passphrase?: string;
 }
 
+export interface IHttpGlobalAgentOptions {
+    keepAlive?: boolean;
+    timeout?: number;
+}
+
 export interface IRequestQueryParams {
     options?: {
         separator?: string,

package.json

@@ -1,6 +1,6 @@
 {
   "name": "typed-rest-client",
-  "version": "2.0.2",
+  "version": "2.1.0",
   "description": "Node Rest and Http Clients for use with TypeScript",
   "main": "./RestClient.js",
   "scripts": {