(PHP 5, PHP 7, PECL OCI8 >= 1.1.0)
OCI-Lob::flush — Flushes/writes buffer of the LOB to the server
$flag
  ] ) : boolOCI-Lob::flush() actually writes data to the server.
flag
       By default, resources are not freed, but using flag 
       OCI_LOB_BUFFER_FREE you can do it explicitly.
       Be sure you know what you're doing - next read/write operation to the
       same part of LOB will involve a round-trip to the server and initialize
       new buffer resources. It is recommended to use 
       OCI_LOB_BUFFER_FREE flag only when you are not
       going to work with the LOB anymore.
      
   成功时返回 TRUE, 或者在失败时返回 FALSE。
  
   Returns FALSE if buffering was not enabled or an error occurred.