public void
	send(int n) {
		sent[n]++;
		outstanding++;
		try {
			inprogress[n] = resolvers[n].sendAsync(query, this);
		}
		catch (Throwable t) {
			synchronized (this) {
				thrown = t;
				done = true;
				if (listener == null) {
					notifyAll();
					return;
				}
			}
		}
	}
An implementation of Resolver that can send queries to multiple servers,
sending the queries multiple times if necessary.
@see Resolver

@author Brian Wellington
src/main/java/core/org/xbill/DNS/ExtendedResolver.java