Rework telemetry to replace the use of tracing with an object we pass around (#8143)

polkadot companion: paritytech/polkadot#2535

substrate/client/telemetry/src/error.rs

@@ -0,0 +1,31 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+#[allow(missing_docs)]
+#[derive(Debug, thiserror::Error)]
+pub enum Error {
+	#[error("IO Error")]
+	IoError(#[from] std::io::Error),
+	#[error("This telemetry instance has already been initialized!")]
+	TelemetryAlreadyInitialized,
+	#[error("The telemetry worker has been dropped already.")]
+	TelemetryWorkerDropped,
+}
+
+#[allow(missing_docs)]
+pub type Result<T> = std::result::Result<T, Error>;