doc: update README example

Author: ymgyt

README.md

@@ -9,32 +9,24 @@ tracing-cloudwatch is a custom tracing-subscriber layer that sends your applicat
 feature `rusoto` required
 
 ```rust
-use rusoto_core::Region;
 use tracing_subscriber::{layer::SubscriberExt, util::SubscriberInitExt};
 
 #[tokio::main]
 async fn main() {
-    let cw_client = rusoto_logs::CloudWatchLogsClient::new(Region::ApNortheast1);
+    let cw_client = rusoto_logs::CloudWatchLogsClient::new(rusoto_core::Region::ApNortheast1);
 
     tracing_subscriber::registry::Registry::default()
         .with(
             tracing_cloudwatch::layer().with_client(
                 cw_client,
                 tracing_cloudwatch::ExportConfig::default()
-                    .with_batch_size(1)
+                    .with_batch_size(5)
                     .with_interval(Duration::from_secs(1))
                     .with_log_group_name("tracing-cloudwatch")
                     .with_log_stream_name("stream-1"),
             ),
         )
         .init();
-
-    start().await;
-}
-
-#[tracing::instrument()]
-async fn start() {
-    tracing::info!("Starting...");
 }
 ```
 
@@ -43,9 +35,10 @@ async fn start() {
 feature `awssdk` required
 
 ```rust
+use tracing_subscriber::{layer::SubscriberExt, util::SubscriberInitExt};
+
 #[tokio::main]
 async fn main() {
-    use tracing_subscriber::{filter, fmt, layer::SubscriberExt, util::SubscriberInitExt};
     let config = aws_config::load_from_env().await;
     let cw_client = aws_sdk_cloudwatchlogs::Client::new(&config);
 
@@ -54,20 +47,13 @@ async fn main() {
             tracing_cloudwatch::layer().with_client(
                 cw_client,
                 tracing_cloudwatch::ExportConfig::default()
-                    .with_batch_size(1)
+                    .with_batch_size(5)
                     .with_interval(Duration::from_secs(1))
                     .with_log_group_name("tracing-cloudwatch")
                     .with_log_stream_name("stream-1"),
             ),
         )
         .init();
-
-    start().await;
-}
-
-#[tracing::instrument()]
-async fn start() {
-    tracing::info!("Starting...");
 }
 ```