Avoid rebuilding clean query strings

Add a lazy query-string encoder that mirrors the existing path encoder
fast path. When a query contains only pass-through characters,
UriEncoder now reuses the original String instead of allocating a
pooled StringBuilder and an equal replacement String.

The append-based path is unchanged for URLs with additional query
params. Existing escaping behavior is preserved for queries that need
percent-encoding.

Codex on behalf of Pavel Ptashyts

Co-Authored-By: Codex <codex@openai.com>

Author: pavel-ptashyts

client/src/main/java/org/asynchttpclient/util/UriEncoder.java

@@ -62,9 +62,7 @@ protected String withQueryWithParams(final String query, final List<Param> query
         @Override
         protected String withQueryWithoutParams(final String query) {
             // encode query
-            StringBuilder sb = StringBuilderPool.DEFAULT.stringBuilder();
-            encodeAndAppendQuery(sb, query);
-            return sb.toString();
+            return Utf8UrlEncoder.encodeQuery(query);
         }
 
         @Override

client/src/main/java/org/asynchttpclient/util/Utf8UrlEncoder.java

@@ -129,6 +129,11 @@ public static String encodePath(String input) {
         return sb == null ? input : sb.toString();
     }
 
+    public static String encodeQuery(String input) {
+        StringBuilder sb = lazyAppendEncoded(null, input, BUILT_QUERY_UNTOUCHED_CHARS, false);
+        return sb == null ? input : sb.toString();
+    }
+
     public static StringBuilder encodeAndAppendQuery(StringBuilder sb, String query) {
         return appendEncoded(sb, query, BUILT_QUERY_UNTOUCHED_CHARS, false);
     }

client/src/test/java/org/asynchttpclient/util/Utf8UrlEncoderTest.java

@@ -18,6 +18,8 @@
 import io.github.artsok.RepeatedIfExceptionsTest;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotSame;
+import static org.junit.jupiter.api.Assertions.assertSame;
 
 public class Utf8UrlEncoderTest {
 
@@ -28,6 +30,22 @@ public void testBasics() {
         assertEquals("a%2Bb", Utf8UrlEncoder.encodeQueryElement("a+b"));
     }
 
+    @RepeatedIfExceptionsTest(repeats = 5)
+    public void encodeQueryReusesInputWhenNothingNeedsEscaping() {
+        String query = "a=1&b=/two?c%20d";
+
+        assertSame(query, Utf8UrlEncoder.encodeQuery(query));
+    }
+
+    @RepeatedIfExceptionsTest(repeats = 5)
+    public void encodeQueryEscapesWhenNeeded() {
+        String query = "a=one two";
+        String encoded = Utf8UrlEncoder.encodeQuery(query);
+
+        assertNotSame(query, encoded);
+        assertEquals("a=one%20two", encoded);
+    }
+
     @RepeatedIfExceptionsTest(repeats = 5)
     public void testPercentageEncoding() {
         assertEquals("foobar", Utf8UrlEncoder.percentEncodeQueryElement("foobar"));