add quick_error

quick_error/src/main.rs

@@ -0,0 +1,22 @@
+#[macro_use] extern crate quick_error;
+
+quick_error! {
+    #[derive(Debug)]
+    pub enum SomeError {
+        Io(m: String) {
+            display("{}", m)
+        }
+        Utf8(err: std::str::Utf8Error) {
+            display("utf8 error")
+        }
+    }
+}
+
+// https://docs.rs/quick-error/1.2.3/quick_error/
+fn main() -> Result<(), SomeError> {
+    println!("Hello, world!");
+
+    Err(SomeError::Io("m".to_owned()))
+}
+
+