The ESP’s IP stack seems not to support UDP packet fragmentation and
drops such packets silently which is problematic for setups with many
LEDs and huge updates.
With this patch, the UDP server processes up to 3 full UDP packets per
frame, allowing much larger updates. Additionally, the new END_OF_UPDATE
flag allows to signal when a update sequence is finished. If this flag
is encountered, no further UDP packets are processed in the current
frame.
The ACK request packet contains a sequence number which is echoed back
to the client in a simple UDP packet. By evaluating the difference
between sent and received sequence number, the client can control how
much data is buffered on the way to the ESP.
Thomas Kolb