returns the round trip time for this ping in nanoseconds , waiting for the response to arrive if necessary . returns -1 if the response was cancelled . concode_field_sep long sent concode_elem_sep CountDownLatch latch concode_elem_sep long received concode_field_sep void cancel concode_elem_sep void receive concode_elem_sep void send
long function ( ) { latch . await ( ) ; return received - sent ; }