add manual sealing

doc/example.md

@@ -41,11 +41,13 @@ gcli ud claim
 gcli account transfer 5000 5E4i8vcNjnrDp21Sbnp32WHm2gz8YP3GGFwmdpfg5bHd8Whb
 ```
 
-If you want to submit extrinsics without tracking progress:
+For testing purpose it can be useful to submit extrinsic without waiting for result and create block manually. 
 
 ```sh
 # only submit extrinsic to network and do not listen to result
 gcli --no-wait account transfer 1234 5FeggKqw2AbnGZF9Y9WPM2QTgzENS3Hit94Ewgmzdg5a3LNa
+# create block manually (with manual sealing)
+gcli blockchain create-block
 ```
 
 ## Indexer commands

src/commands/blockchain.rs

@@ -18,6 +18,9 @@ pub enum Subcommand {
 	/// Check current block
 	#[default]
 	CurrentBlock,
+	/// Create one block manually (manual sealing)
+	#[clap(hide = true)]
+	CreateBlock,
 }
 
 /// handle blockchain commands
@@ -46,6 +49,12 @@ pub async fn handle_command(data: Data, command: Subcommand) -> anyhow::Result<(
 					.unwrap()
 			);
 		}
+		Subcommand::CreateBlock => {
+			data.client()
+				.rpc()
+				.request("engine_createBlock", subxt::rpc::rpc_params![true, true]) // create empty block and finalize
+				.await?; // FIXME this gives a serialization error
+		}
 	}
 	Ok(())
 }