Fix UnsupportedOperationException when modifying headers (#93)

* copy passed headers into an ArrayList before setting them to avoid UnsupportedOperationException's

CHANGELOG.md

@@ -5,6 +5,11 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.31.1] - 2024-10-09
+
+### Fixed
+- Override the lombok generated `TkmsMessage#setHeaders` to copy the passed headers into a mutable `ArrayList` in order to avoid `UnsupportedOperationException`
+
 ## [0.31.0] - 2024-10-07
 
 ### Changed

gradle.properties

@@ -1 +1 @@
-version=0.31.0
+version=0.31.1

tw-tkms-starter/src/main/java/com/transferwise/kafka/tkms/api/TkmsMessage.java

@@ -6,6 +6,7 @@
 import java.nio.charset.StandardCharsets;
 import java.time.Instant;
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import java.util.UUID;
@@ -107,6 +108,17 @@ public TkmsMessage addPriorityHeader(long priority) {
     );
   }
 
+  /**
+   * Copy the passed headers into a ModifiableList to avoid UnsupportedOperationException when `addHeader` is called.
+   * @param headers headers to copy
+   * @return TkmsMessage
+   */
+  public TkmsMessage setHeaders(List<Header> headers) {
+    this.headers = new ArrayList<>(headers);
+
+    return this;
+  }
+
   public TkmsMessage addHeader(Header header) {
     if (headers == null) {
       headers = new ArrayList<>();