question: public synchronized boolean addReceiver ( SpanReceiver receiver ) { SpanReceiver [ ] receivers = curReceivers ; for ( int i = 0 ; i < receivers . length ; i ++ ) { if ( receivers [ i ] == receiver ) { LOG . trace ( toString ( ) + ": can't add receiver " + receiver . toString ( ) + " since it is already in this pool." ) ; return false ; } } SpanReceiver [ ] newReceivers = Arrays . copyOf ( receivers , receivers . length + 1 ) ; newReceivers [ receivers . length ] = receiver ; registerShutdownHookIfNeeded ( ) ; curReceivers = newReceivers ; LOG . trace ( toString ( ) + ": added receiver " + receiver . toString ( ) ) ; return true ; }
target:  Add a new span receiver.