Get rid of some pointless pin_project stuff (#14212)

substrate/Cargo.lock

@@ -9621,7 +9621,6 @@ dependencies = [
  "libp2p",
  "log",
  "parity-scale-codec",
- "pin-project",
  "sc-network",
  "sc-network-common",
  "sc-peerset",

substrate/client/network/transactions/Cargo.toml

@@ -18,7 +18,6 @@ codec = { package = "parity-scale-codec", version = "3.2.2", features = ["derive
 futures = "0.3.21"
 libp2p = "0.51.3"
 log = "0.4.17"
-pin-project = "1.0.12"
 prometheus-endpoint = { package = "substrate-prometheus-endpoint", version = "0.10.0-dev", path = "../../../utils/prometheus" }
 sc-network = { version = "0.10.0-dev", path = "../" }
 sc-network-common = { version = "0.10.0-dev", path = "../common" }

substrate/client/network/transactions/src/lib.rs

@@ -97,21 +97,19 @@ impl Metrics {
 	}
 }
 
-#[pin_project::pin_project]
 struct PendingTransaction<H> {
-	#[pin]
 	validation: TransactionImportFuture,
 	tx_hash: H,
 }
 
+impl<H> Unpin for PendingTransaction<H> {}
+
 impl<H: ExHashT> Future for PendingTransaction<H> {
 	type Output = (H, TransactionImport);
 
-	fn poll(self: Pin<&mut Self>, cx: &mut std::task::Context<'_>) -> Poll<Self::Output> {
-		let mut this = self.project();
-
-		if let Poll::Ready(import_result) = Pin::new(&mut this.validation).poll_unpin(cx) {
-			return Poll::Ready((this.tx_hash.clone(), import_result))
+	fn poll(mut self: Pin<&mut Self>, cx: &mut std::task::Context<'_>) -> Poll<Self::Output> {
+		if let Poll::Ready(import_result) = self.validation.poll_unpin(cx) {
+			return Poll::Ready((self.tx_hash.clone(), import_result))
 		}
 
 		Poll::Pending