Snapshot sync part 2 (#2098)

* Split block downloader into a module

* Snapshot sync progress

* Warp sync CLI option

* Increased snapshot chunk and ping timeouts

* Fixed an issue with delayed writes

* Updated bootnodes

* Don't run pending IO tasks on shutdown

* Optional first_block; removed insert_snapshot_block

* Fixing expect calls

* Fixed stalled sync

* style and docs

* Update block_sync.rs

[ci:skip]

parity/cli/config.full.toml

@@ -28,6 +28,7 @@ nat = "any"
 id = "0x1"
 bootnodes = []
 discovery = true
+warp = true
 
 reserved_only = false
 reserved_peers = "./path_to_file"

parity/cli/config.toml

@@ -13,6 +13,7 @@ disable = true
 
 [network]
 disable = false
+warp = false
 discovery = true
 nat = "any"
 min_peers = 10

parity/cli/mod.rs

@@ -106,6 +106,8 @@ usage! {
 		// -- Networking Options
 		flag_no_network: bool = false,
 			or |c: &Config| otry!(c.network).disable.clone(),
+		flag_warp: bool = false,
+			or |c: &Config| otry!(c.network).warp.clone(),
 		flag_port: u16 = 30303u16,
 			or |c: &Config| otry!(c.network).port.clone(),
 		flag_min_peers: u16 = 25u16,
@@ -300,6 +302,7 @@ struct Signer {
 #[derive(Default, Debug, PartialEq, RustcDecodable)]
 struct Network {
 	disable: Option<bool>,
+	warp: Option<bool>,
 	port: Option<u16>,
 	min_peers: Option<u16>,
 	max_peers: Option<u16>,
@@ -486,6 +489,7 @@ mod tests {
 
 			// -- Networking Options
 			flag_no_network: false,
+			flag_warp: true,
 			flag_port: 30303u16,
 			flag_min_peers: 25u16,
 			flag_max_peers: 50u16,
@@ -643,6 +647,7 @@ mod tests {
 			}),
 			network: Some(Network {
 				disable: Some(false),
+				warp: Some(false),
 				port: None,
 				min_peers: Some(10),
 				max_peers: Some(20),

parity/cli/usage.txt

@@ -67,6 +67,7 @@ Account Options:
 
 Networking Options:
   --no-network             Disable p2p networking. (default: {flag_no_network})
+  --warp                   Enable syncing from the snapshot over the network. (default: {flag_warp})
   --port PORT              Override the port on which the node should listen
                            (default: {flag_port}).
   --min-peers NUM          Try to maintain at least NUM peers (default: {flag_min_peers}).