diff --git a/pkg/analysis_server/lib/src/server/lsp_stdio_server.dart b/pkg/analysis_server/lib/src/server/lsp_stdio_server.dart
index 1b5cde5..92fd980 100644
--- a/pkg/analysis_server/lib/src/server/lsp_stdio_server.dart
+++ b/pkg/analysis_server/lib/src/server/lsp_stdio_server.dart
@@ -33,7 +33,7 @@
    */
   Future serveStdio() {
     LspByteStreamServerChannel serverChannel = new LspByteStreamServerChannel(
-        stdin, stdout, socketServer.instrumentationService);
+        stdin, stdout.nonBlocking, socketServer.instrumentationService);
     socketServer.createAnalysisServer(serverChannel);
     return serverChannel.closed;
   }