fix(pdi-scanner): use a smaller USB buffer in development

libs/pdi-scanner/build.rs

@@ -0,0 +1,13 @@
+fn main() {
+    println!("cargo::rustc-check-cfg=cfg(production)");
+    println!("cargo:rerun-if-env-changed=NODE_ENV");
+
+    let is_production = match std::env::var("NODE_ENV") {
+        Ok(env) => env == "production",
+        Err(_) => false,
+    };
+
+    if is_production {
+        println!("cargo:rustc-cfg=production");
+    }
+}

libs/pdi-scanner/src/rust/scanner.rs

@@ -82,8 +82,15 @@ impl Scanner {
         /// bit trying to catch the paper, we might need a bit more. So for any
         /// reasonable paper size, 4 MB should be plenty and doesn't really put
         /// a dent in available memory.
+        #[cfg(production)]
         const BUFFER_SIZE: usize = 4_194_304;
 
+        /// For development, we want a smaller buffer because, for reasons we
+        /// don't understand, communicating with the scanner times out with a
+        /// larger buffer.
+        #[cfg(not(production))]
+        const BUFFER_SIZE: usize = 16_384;
+
         let (host_to_scanner_tx, host_to_scanner_rx) =
             mpsc::channel::<(usize, packets::Outgoing)>();
         let (host_to_scanner_ack_tx, host_to_scanner_ack_rx) = mpsc::channel::<usize>();