staking-miner: CLI flag delay solution x secs

utils/staking-miner/src/monitor.rs

@@ -198,6 +198,7 @@ macro_rules! monitor_cmd_for { ($runtime:tt) => { paste::paste! {
 				return;
 			}
 
+
 			let rpc1 = rpc.clone();
 			let rpc2 = rpc.clone();
 			let account = signer.account.clone();
@@ -206,6 +207,8 @@ macro_rules! monitor_cmd_for { ($runtime:tt) => { paste::paste! {
 				ensure_signed_phase::<Runtime, Block>(&rpc1, hash).await
 			});
 
+			tokio::time::sleep(std::time::Duration::from_secs(config.delay as u64)).await;
+
 			let no_prev_sol_fut = tokio::spawn(async move {
 				ensure_no_previous_solution::<Runtime, Block>(&rpc2, hash, &account).await
 			});

utils/staking-miner/src/opts.rs

@@ -83,6 +83,17 @@ pub(crate) struct MonitorConfig {
 	/// `--submission-strategy "percent-better <percent>"`: submit if the submission is `n` percent better.
 	#[clap(long, parse(try_from_str), default_value = "if-leading")]
 	pub submission_strategy: SubmissionStrategy,
+
+	/// Delay in number seconds to wait until starting mining a solution.
+	///
+	/// At every block when a solution is attempted
+	/// a delay can be enforced to avoid submitting at
+	/// "same" time and risk the potentially races to other miners.
+	///
+	/// This may mean if there are competing solutions you might not submit
+	/// if the scores are equal once this is enabled.
+	#[clap(long, parse(try_from_str), default_value_t = 0)]
+	pub delay: usize,
 }
 
 #[derive(Debug, Clone, Parser)]