Add UnsynchronizedBufferedReader.unwrap() (#850)

Author: garydgregory

src/main/java/org/apache/commons/io/input/UnsynchronizedBufferedReader.java

@@ -482,4 +482,17 @@ public long skip(final long amount) throws IOException {
         return amount;
     }
 
+    /**
+     * Unwraps this instance by returning the underlying {@link Reader}.
+     * <p>
+     * Use with caution.
+     * </p>
+     *
+     * @return the underlying {@link Reader}.
+     * @since 2.23.0
+     */
+    public Reader unwrap() {
+        return in;
+    }
+
 }

src/test/java/org/apache/commons/io/input/UnsynchronizedBufferedReaderTest.java

@@ -21,6 +21,7 @@
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertSame;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
@@ -633,4 +634,12 @@ void testSkipIllegal() throws IOException {
         br = new UnsynchronizedBufferedReader(new StringReader(testString));
         assertThrows(IllegalArgumentException.class, () -> br.skip(-1));
     }
+
+    @SuppressWarnings("resource")
+    @Test
+    void testUnwrap() throws IOException {
+        final StringReader reader = new StringReader(testString);
+        br = new UnsynchronizedBufferedReader(reader);
+        assertSame(reader, br.unwrap());
+    }
 }