Add "tui" feature.

Cargo.toml

@@ -38,6 +38,7 @@ url = {version = "2.2.2", optional = true}
 
 # Misc
 num-bigint = {version = "0.4.3", optional = true}
+termion = {version = "1.5.6", optional = true}
 
 # Websockets
 tungstenite = {version = "0.16.0", optional = true}
@@ -59,6 +60,7 @@ websockets = ["tungstenite", "async-tungstenite"]
 util = ["async-runtime", "hex", "serde", "serde_json", "dirs", "num-bigint"]
 rpc = ["async-net", "util", "websockets", "url"]
 chain = ["rocksdb", "util"]
+tui = ["async-std", "termion"]
 
 # [dependencies.halo2_gadgets]
 # git = "https://github.com/parazyd/halo2_gadgets.git"

src/error.rs

@@ -199,7 +199,6 @@ impl From<serde_json::Error> for Error {
     }
 }
 
-#[cfg(feature = "util")]
 impl From<std::io::Error> for Error {
     fn from(err: std::io::Error) -> Error {
         Error::Io(err.kind())