EthernetUDP.write()

// An EthernetUDP instance to let us send and receive packets over UDP
EthernetUDP Udp;

Udp.write(message);
Udp.write(buffer, size);

#include <Ethernet.h>
#include <EthernetUdp.h> 
// Enter an IP address for your controller below.
// The IP address will be dependent on your local network:
IPAddress ip(192, 168, 1, 177);
unsigned int localPort = 8888;      // local port to listen on
// An EthernetUDP instance to let us send and receive packets over UDP
EthernetUDP Udp;
 
void setup() {
  // start the Ethernet and UDP:
  Ethernet.begin(NULL,ip);
  Udp.begin(localPort);
}
 
void loop() {
  Udp.beginPacket(Udp.remoteIP(), Udp.remotePort());
  Udp.write("hello");
  Udp.endPacket();
}