title: JSR-310 - parsing seconds fraction with variable length
body: <p>Is there a way how to create JSR-310 formatter that is able to parse both following date/times with variable length of seconds fraction?</p>
  
  <pre><code>2015-05-07 13:20:22.276052
  </code></pre>
  
  <p>or</p>
  
  <pre><code>2015-05-07 13:20:22.276
  </code></pre>
  
  <p>Example code:</p>
  
  <pre><code>DateTimeFormatter formatter
  = new java.time.format.DateTimeFormatterBuilder()
          .append( java.time.format.DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss") )
          .appendOptional( java.time.format.DateTimeFormatter.ofPattern(".SSSSSS") )
          .toFormatter();
  formatter.parse("2015-05-07 13:20:22.276052", LocalDateTime::from);
  </code></pre>