public static void storeBuffer(ByteBuf buf, Object message, RequestContext ctx) {
        IdentityHashMap<Object, ByteBuf> buffers = ctx.attr(BUFFERS);
        if (buffers == null) {
            buffers = new IdentityHashMap<>();
            ctx.setAttr(BUFFERS, buffers);
        }
        buffers.put(message, buf);
    }
Stores the {@link ByteBuf} backing the specified {@link Message} to be released later using
{@link #releaseBuffer(Object, RequestContext)}.
grpc/src/main/java/com/linecorp/armeria/unsafe/grpc/GrpcUnsafeBufferUtil.java