title: Using pyarrow how do you append to parquet file?
body: <p>How do you append/update to a <code>parquet</code> file with <code>pyarrow</code>? </p>
  
  <pre><code>import pandas as pd
  import pyarrow as pa
  import pyarrow.parquet as pq
  
  
   table2 = pd.DataFrame({'one': [-1, np.nan, 2.5], 'two': ['foo', 'bar', 'baz'], 'three': [True, False, True]})
   table3 = pd.DataFrame({'six': [-1, np.nan, 2.5], 'nine': ['foo', 'bar', 'baz'], 'ten': [True, False, True]})
  
  
  pq.write_table(table2, './dataNew/pqTest2.parquet')
  #append pqTest2 here?  
  </code></pre>
  
  <p>There is nothing I found in the docs about appending parquet files. And, Can you use <code>pyarrow</code>  with multiprocessing to insert/update the data. </p>