source.sendAsync(df, null, senderCounter);
PartiallyReceivedBlock prb =
new PartiallyReceivedBlock(Node.PACKETS_IN_BLOCK, Node.PACKET_SIZE, block.getRawData());
final BlockTransmitter bt =
new BlockTransmitter(node.usm, node.getTicker(), source, uid, prb, senderCounter, BlockTransmitter.NEVER_CASCADE,
new BlockTransmitterCompletion() {
@Override
public void blockTransferFinished(boolean success) {
tag.unlockHandler();
}