How to get the body of an HTTP request?

Question

I want to read a binary body datas from an HTTP POST request.

The context is that I'm making a LED strip controller and I'm currently using this code :

#include <WebServer.h>
#include <Adafruit_NeoPixel.h>

Adafruit_NeoPixel strip = Adafruit_NeoPixel(LED_COUNT, STRIP_PIN, NEO_GRB | NEO_KHZ800);
WebServer server(80);

void handleSimpleWrite()
{
    int r = 0, g = 0, b = 0;
    if (server.hasArg("red"))
        r = server.arg("red").toInt();
    if (server.hasArg("green"))
        g = server.arg("green").toInt();
    if (server.hasArg("blue"))
        b = server.arg("blue").toInt();
    strip.setPixelColor(id, r, g, b);
    strip.show()
    server.send(200,"Ok");
}

It works, but it's clearly innefficient. I want to make an API endpoint that get a binary buffer with RGB states along the request body and I can't figure out how to read this body.

Any ideas ?