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lib/presto-client/index.js

@@ -108,6 +108,11 @@ Client.prototype.request = function(opts, callback) {
     if (opts.body)
         contentBody = opts.body;
 
+    // `agents` is a custom property that follow-redirects supports, where
+    // it's similar to setting `agent`, but allows for setting it per protocol,
+    // so that if we redirect from http -> https (or vice versa) we use the right
+    // agent, instead of trying to reuse http.Agent for https (or vice versa) which
+    // will error.
     opts.agents = {
         http: new http.Agent({ keepAlive: false }),
         https: new https.Agent({ ...client.ssl, keepAlive: false }),