Write data to the server the client is connected to. This data is sent as a byte or series of bytes.
client.write(val) client.write(buf, len)
val: a value to send as a single byte (byte or char)
buf: an array to send as a series of bytes (byte or char)
len: the length of the buffer
byte write() returns the number of bytes written. It is not necessary to read this value.