add periodic delay in analysis to reduce request processing latency

pkg/analysis_server/lib/src/get_handler.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library analysis_server.src.get_handler;
 
 import 'dart:collection';
 import 'dart:convert';
 import 'dart:io';
 import 'dart:math';
@@ skipping 1056 matching lines @@
       _writeOption(
           buffer,
           'Incremental resolution with API changes',
           options.incrementalApi);
       _writeOption(
           buffer,
           'Preserve comments',
           options.preserveComments,
           last: true);
       buffer.write('</p>');
+      int freq = AnalysisServer.performOperationDelayFreqency;
+      String delay = freq > 0 ? '1 ms every $freq ms' : 'off';
+      buffer.write('<p><b>perform operation delay:</b> $delay</p>');
     }, (StringBuffer buffer) {
       _writeSubscriptionMap(
           buffer,
           AnalysisService.VALUES,
           analysisServer.analysisServices);
     });
   }
 
   /**
    * Write performance information about a specific completion request
@@ skipping 541 matching lines @@
     } else if (value is Element) {
       String link =
           _makeLink(ELEMENT_PATH, linkParameters, value.runtimeType.toString());
       buffer.write('<i>$link</i>');
     } else {
       buffer.write(HTML_ESCAPE.convert(value.toString()));
       buffer.write(' <i>(${value.runtimeType.toString()})</i>');
     }
   }
 }