title: Issue about utf-8-sig encoding and tab delimiter on csv file
body: <p>I want to save some DataFrame data to csv file with '\t' delimiter, and because there are Chinese characters in data so use <code>utf-8-sig</code> encoding. But encountered a issue that Excel can't auto load columns correctly when both <code>utf-8-sig</code> encoding and '\t' delimiter.</p>
  
  <p>Firstly, code as follows:</p>
  
  <pre><code>import pandas as pd
  df = pd.DataFrame({'A': [1, 2, 3, 4], 'B': ['a', 'b\tc', '你好', 'test code']})
  # case1
  df.to_csv('case1.csv', encoding='utf-8', index=False)
  # case2
  df.to_csv('case2.csv', encoding='utf-8-sig', index=False)
  # case3
  df.to_csv('case3.csv', encoding='utf-8-sig', sep='\t'.encode('utf-8'), index=False)
  df.to_csv('case4.csv', encoding='utf-8', sep='\t'.encode('utf-8'), index=False)
  </code></pre>
  
  <p>The result as follows(open case file with excel):</p>
  
  <p>case1.csv:<a href="https://i.stack.imgur.com/cfmvs.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/cfmvs.png" alt="enter image description here"></a> </p>
  
  <p>case2.csv:<a href="https://i.stack.imgur.com/bKXgr.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/bKXgr.png" alt="enter image description here"></a></p>
  
  <p>case3.csv:<a href="https://i.stack.imgur.com/VnJUG.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/VnJUG.png" alt="enter image description here"></a></p>
  
  <p>case4.csv:<a href="https://i.stack.imgur.com/ilGg1.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/ilGg1.png" alt="enter image description here"></a></p>
  
  <p>So how modify the code when both <code>utf-8-sig</code> and '\t' delimiter that Excel can auto load columns correctly?</p>
  
  <p>Thanks in advance.</p>