Use Assert.state() where appropriate

spring-r2dbc/src/main/java/org/springframework/r2dbc/connection/ConnectionHolder.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -23,7 +23,6 @@ import org.springframework.lang.Nullable;
 import org.springframework.transaction.support.ResourceHolderSupport;
 import org.springframework.util.Assert;
 
-
 /**
  * Resource holder wrapping a R2DBC {@link Connection}.
  * {@link R2dbcTransactionManager} binds instances of this class to the subscription,
@@ -109,7 +108,7 @@ public class ConnectionHolder extends ResourceHolderSupport {
 	 * @see #released()
 	 */
 	public Connection getConnection() {
-		Assert.notNull(this.currentConnection, "Active Connection is required");
+		Assert.state(this.currentConnection != null, "Active Connection is required");
 		return this.currentConnection;
 	}