Proposed update to enable reconnect on first attempt

src/asynk.rs

@@ -636,6 +636,28 @@ impl Options {
         }
     }
 
+    /// Select option to enable reconnect with backoff
+    /// on first failed connection attempt.
+    /// The reconnect logic with `max_reconnects` and the
+    /// `reconnect_delay_callback` will be specified the same
+    /// as before but will be invoked on the first failed
+    /// connection attempt.
+    ///
+    /// # Example
+    /// ```
+    /// # smol::block_on(async {
+    /// let nc = nats::asynk::Options::new()
+    ///     .retry_on_failed_connect()
+    ///     .connect("demo.nats.io")
+    ///     .await?;
+    /// # std::io::Result::Ok(()) });
+    /// ```
+    pub fn retry_on_failed_connect(self) -> Options {
+        Options {
+            inner: self.inner.retry_on_failed_connect(),
+        }
+    }
+
     /// Set the maximum number of reconnect attempts.
     /// If no servers remain that are under this threshold,
     /// then no further reconnect shall be attempted.

src/client.rs

@@ -519,8 +519,9 @@ impl Client {
         let mut first_connect = true;
 
         loop {
-            // Don't use backoff on first connect.
-            let use_backoff = !first_connect;
+            //  Don't use backoff on first connect unless retry_on_failed_connect is set to true.
+            let use_backoff = self.options.retry_on_failed_connect || !first_connect;
+
             // Make a connection to the server.
             let (server_info, stream) = connector.connect(use_backoff)?;
 

src/options.rs

@@ -15,6 +15,7 @@ pub struct Options {
     pub(crate) auth: AuthStyle,
     pub(crate) name: Option<String>,
     pub(crate) no_echo: bool,
+    pub(crate) retry_on_failed_connect: bool,
     pub(crate) max_reconnects: Option<usize>,
     pub(crate) reconnect_buffer_size: usize,
     pub(crate) tls_required: bool,
@@ -36,6 +37,7 @@ impl fmt::Debug for Options {
             .entry(&"auth", &self.auth)
             .entry(&"name", &self.name)
             .entry(&"no_echo", &self.no_echo)
+            .entry(&"retry_on_failed_connect", &self.retry_on_failed_connect)
             .entry(&"reconnect_buffer_size", &self.reconnect_buffer_size)
             .entry(&"max_reconnects", &self.max_reconnects)
             .entry(&"tls_required", &self.tls_required)
@@ -57,6 +59,7 @@ impl Default for Options {
             auth: AuthStyle::NoAuth,
             name: None,
             no_echo: false,
+            retry_on_failed_connect: false,
             reconnect_buffer_size: 8 * 1024 * 1024,
             max_reconnects: Some(60),
             tls_required: false,
@@ -383,6 +386,27 @@ impl Options {
         self
     }
 
+    /// Select option to enable reconnect with backoff
+    /// on first failed connection attempt.
+    /// The reconnect logic with `max_reconnects` and the
+    /// `reconnect_delay_callback` will be specified the same
+    /// as before but will be invoked on the first failed
+    /// connection attempt.
+    ///
+    /// # Example
+    /// ```
+    /// # fn main() -> std::io::Result<()> {
+    /// let nc = nats::Options::new()
+    ///     .retry_on_failed_connect()
+    ///     .connect("demo.nats.io")?;
+    /// # Ok(())
+    /// # }
+    /// ```
+    pub fn retry_on_failed_connect(mut self) -> Options {
+        self.retry_on_failed_connect = true;
+        self
+    }
+
     /// Set the maximum number of reconnect attempts.
     /// If no servers remain that are under this threshold,
     /// then no further reconnect shall be attempted.