Stackless variant of NoTransactionException for reactive flows

Closes gh-23360

spring-tx/src/main/java/org/springframework/transaction/reactive/TransactionContextManager.java

@@ -62,7 +62,7 @@ public abstract class TransactionContextManager {
 					return;
 				}
 			}
-			sink.error(new NoTransactionException("No transaction in context"));
+			sink.error(new NoTransactionInContextException());
 		});
 	}
 
@@ -111,4 +111,22 @@ public abstract class TransactionContextManager {
 		};
 	}
 
+
+	/**
+	 * Stackless variant of {@link NoTransactionException} for reactive flows.
+	 */
+	@SuppressWarnings("serial")
+	private static class NoTransactionInContextException extends NoTransactionException {
+
+		public NoTransactionInContextException() {
+			super("No transaction in context");
+		}
+
+		@Override
+		public synchronized Throwable fillInStackTrace() {
+			// stackless exception
+			return this;
+		}
+	}
+
 }