title: BrowserSync.stream() not working, browserSync.reload() throws error
body: <p>This is my Gulp file:</p>
  
  <pre><code>var gulp = require('gulp'),
      watch = require('gulp-watch'),
      postcss = require('gulp-postcss'),
      autoprefixer = require('autoprefixer'),
      simplevars = require('postcss-simple-vars'),
      nested = require('postcss-nested'),
      cssImport = require('postcss-import'),
      browserSync = require('browser-sync').create();
  
  gulp.task('default', function() {   
    console.log("Test to see if gulp is running");
  });
  
  gulp.task('html', function() {
    console.log("Something happening to my html");
  });
  
  gulp.task('styles', function() {
    return gulp.src('./app/assets/styles/styles.css')
    .pipe(postcss([cssImport, simplevars, nested, autoprefixer]))
    .pipe(gulp.dest('./app/temp/styles'));
  });
  
  gulp.task('cssInject', ['styles'], function() {
    return gulp.src('.app/temp/styles/styles.css')
    .pipe(browserSync.stream());
  });
  
  gulp.task('watch', function() {
    browserSync.init({
      notify:false,
      server: {
        baseDir: "app"
      }
    });
  
    watch('./app/index.html', function() {
      browserSync.reload();
    });
  
    watch('./app/assets/styles/**/*.css', function() {
      gulp.start('cssInject');
    });
  });
  </code></pre>
  
  <p>When I run the <code>gulp watch</code> task, <code>index.html</code> file reloads as expected. But the <code>cssInject task</code> does not reload the page, nor does it inject the css changes. It does nothing. If I change the <code>.pipe(browserSync.stream());</code> to <code>.pipe(browserSync.reload());</code>, it reloads + updates the changes, but I get this error:</p>
  
  <pre><code>[BS] Reloading Browsers...
  [11:15:36] 'cssInject' errored after 22 ms
  [11:15:36] TypeError: Cannot read property 'on' of undefined
      at DestroyableTransform.Readable.pipe (C:\Users\z\OneDrive\NewWebsite\node_modules\vinyl-fs\node_modules\readable-stream\lib\_stream_readable.js:516:7)
      at Gulp.&lt;anonymous&gt; (C:\Users\z\OneDrive\NewWebsite\gulpfile.js:34:4)
      at module.exports (C:\Users\z\OneDrive\NewWebsite\node_modules\orchestrator\lib\runTask.js:34:7)
      at Gulp.Orchestrator._runTask (C:\Users\z\OneDrive\NewWebsite\node_modules\orchestrator\index.js:273:3)
      at Gulp.Orchestrator._runStep (C:\Users\z\OneDrive\NewWebsite\node_modules\orchestrator\index.js:214:10)
      at C:\Users\z\OneDrive\NewWebsite\node_modules\orchestrator\index.js:279:18
      at finish (C:\Users\z\OneDrive\NewWebsite\node_modules\orchestrator\lib\runTask.js:21:8)
      at C:\Users\z\OneDrive\NewWebsite\node_modules\orchestrator\lib\runTask.js:52:4
      at f (C:\Users\z\OneDrive\NewWebsite\node_modules\once\once.js:17:25)
      at DestroyableTransform.onend (C:\Users\z\OneDrive\NewWebsite\node_modules\end-of-stream\index.js:31:18)
      at emitNone (events.js:72:20)
      at DestroyableTransform.emit (events.js:166:7)
      at C:\Users\z\OneDrive\NewWebsite\node_modules\vinyl-fs\node_modules\readable-stream\lib\_stream_readable.js:965:16
      at nextTickCallbackWith0Args (node.js:420:9)
      at process._tickCallback (node.js:349:13)
  </code></pre>
  
  <p>Can anyone suggest what I'm doing wrong? Thank you.</p>
  
  <p>EDITED to add: I have version 2.12.8 of browser-sync.</p>