session.sendDatagram(datagram)
datagram<string> | <ArrayBufferView>- 返回：<bigint>
向远程端发送不可靠的数据报，并返回数据报 ID。如果数据报的有效载荷指定为 ArrayBufferView，则该视图的所有权将转移到底层流。
🌐 Sends an unreliable datagram to the remote peer, returning the datagram ID.
If the datagram payload is specified as an ArrayBufferView, then ownership of
that view will be transfered to the underlying stream.