increase buffer length a bit

src/main.rs

@@ -29,7 +29,7 @@ mod app {
     use crate::spi_data::{self, SpiData};
 
     // in # packets
-    const BUFFER_LEN: usize = 50;
+    const BUFFER_LEN: usize = 150;
 
     // in bytes
     // explicitly make this smaller than a packet so that we don't buffer things in the tx DMA for a while