ob_implicit_flush() will turn implicit flushing on or off (if no flag is given, it defaults to on). Implicit flushing will result in a flush operation after every output call, so that explicit calls to flush() will no longer be needed.
Turning implicit flushing on will disable output buffering, the output buffers current output will be sent as if ob_end_flush() had been called.
See also flush(), ob_start(), and ob_end_flush().