chore(examples): add syslog friendly format (#174)

Closes #157

examples/syslog_friendly_format.rs

@@ -0,0 +1,24 @@
+use std::io::Write;
+
+fn main() {
+    match std::env::var("RUST_LOG_STYLE") {
+        Ok(s) if s == "SYSTEMD" => env_logger::builder()
+            .format(|buf, record| {
+                writeln!(
+                    buf,
+                    "<{}>{}: {}",
+                    match record.level() {
+                        log::Level::Error => 3,
+                        log::Level::Warn => 4,
+                        log::Level::Info => 6,
+                        log::Level::Debug => 7,
+                        log::Level::Trace => 7,
+                    },
+                    record.target(),
+                    record.args()
+                )
+            })
+            .init(),
+        _ => env_logger::init(),
+    };
+}