Implement PassThrough stream to insulate output

lib/machine-as-action.js

@@ -931,8 +931,17 @@ module.exports = function machineAsAction(optsOrMachineDef) {
                     } catch (err) { console.error('Consistency violation: Unexpected internal error:',err); }
                   });//æ
 
+                  // Construct a pass-through stream to adjust for any weirdness
+                  // in the output stream  (e.g. otherwise if it came from the
+                  // `request` package aka sails.helpers.http.*, then it could
+                  // leak headers or other potentially sensitive information, or
+                  // cause compatibility issues.)
+                  // > Note: This PassThrough approach isn't free as far as performance,
+                  // > but we feel it's an acceptable price.  For more on that, see:
+                  // > https://www.vperi.com/archives/520
+                  var passThrough = new Stream.PassThrough();
                   res.status(responses[exitCodeName].statusCode);
-                  return output.pipe(res);
+                  return output.pipe(passThrough).pipe(res);
                 }
                 // • Buffer
                 else if (output instanceof Buffer) {