enable logging for examples and add doc for logging (#199)

examples/query.rs

@@ -16,6 +16,8 @@
 use mdns_sd::{ServiceDaemon, ServiceEvent};
 
 fn main() {
+    env_logger::init();
+
     // Create a daemon
     let mdns = ServiceDaemon::new().expect("Failed to create daemon");
 

examples/register.rs

@@ -15,6 +15,8 @@ use mdns_sd::{DaemonEvent, ServiceDaemon, ServiceInfo};
 use std::{env, thread, time::Duration};
 
 fn main() {
+    env_logger::init();
+
     // Simple command line options.
     let args: Vec<String> = env::args().collect();
     let mut should_unreg = false;

src/lib.rs

@@ -106,6 +106,24 @@
 //! We focus on the common use cases at first, and currently have the following limitations:
 //! - Only support multicast, not unicast send/recv.
 //! - Only support 32-bit or bigger platforms, not 16-bit platforms.
+//!
+//! # Use logging in tests and examples
+//!
+//! Often times it is helpful to enable logging running tests or examples to examine the details.
+//! For tests and examples, we use [`env_logger`](https://docs.rs/env_logger/latest/env_logger/)
+//! as the logger and use [`test-log`](https://docs.rs/test-log/latest/test_log/) to enable logging for tests.
+//! For instance you can show all test logs using:
+//!
+//! ```shell
+//! RUST_LOG=debug cargo test integration_success -- --nocapture
+//! ```
+//!
+//! We also enabled the logging for the examples. For instance you can do:
+//!
+//! ```shell
+//! RUST_LOG=debug cargo run --example query _printer._tcp
+//! ```
+//!
 
 #![forbid(unsafe_code)]
 #![allow(clippy::single_component_path_imports)]