title: org.apache.commons.vfs2.FileSystemException: Could not close the output stream
body: <p>I am using VFS 2.0 for implementing SFTP for my application. I have a single Thread which actually picks up the file and do SFTP. 98% of the time it works. But I have observed there are few cases where SFTP is getting failed with below exception..</p>
  
  <pre><code>Caused by: org.apache.commons.vfs2.FileSystemException: Could not close the output stream for file "sftp://*******************/Test.csv".
      [null,null]at org.apache.commons.vfs2.provider.DefaultFileContent$FileContentOutputStream.close(DefaultFileContent.java:694)
      [null,null]at org.apache.commons.vfs2.FileUtil.copyContent(FileUtil.java:118)
      [null,null]at org.apache.commons.vfs2.provider.AbstractFileObject.copyFrom(AbstractFileObject.java:1053)
      [null,null]... 3 more
  Caused by: java.io.IOException: inputstream is closed
      [null,null]at com.jcraft.jsch.ChannelSftp.fill(ChannelSftp.java:2884)
      [null,null]at com.jcraft.jsch.ChannelSftp.header(ChannelSftp.java:2908)
      [null,null]at com.jcraft.jsch.ChannelSftp.checkStatus(ChannelSftp.java:2446)
      [null,null]at com.jcraft.jsch.ChannelSftp._sendCLOSE(ChannelSftp.java:2465)
      [null,null]at com.jcraft.jsch.ChannelSftp.access$400(ChannelSftp.java:36)
      [null,null]at com.jcraft.jsch.ChannelSftp$1.close(ChannelSftp.java:854)
      [null,null]at java.io.FilterOutputStream.close(FilterOutputStream.java:143)
      [null,null]at org.apache.commons.vfs2.util.MonitorOutputStream.close(MonitorOutputStream.java:56)
      [null,null]at java.io.FilterOutputStream.close(FilterOutputStream.java:143)
      [null,null]at org.apache.commons.vfs2.util.MonitorOutputStream.close(MonitorOutputStream.java:56)
      [null,null]at org.apache.commons.vfs2.provider.DefaultFileContent$FileContentOutputStream.close(DefaultFileContent.java:690)
      [null,null]... 5 more
  </code></pre>
  
  <p>Please suggest what could be the possible reason for the above exception.</p>