Optimize query parameter key=value parsing

[schlosna]

Before this PR

In services that make high throughput RPCs with small responses (think similar clients of timestamps, locks, authorization results, etc. as #3114 ), String#charAt & com.google.common.base.Splitter#splitToList pop up as hot methods & allocators due to DialogueFeignClient.FeignEndpoint#renderPath query parameter key=value parsing.

After this PR

==COMMIT_MSG==
Use vectorized indexOf to improve query parameter parsing and reduce allocation overhead.
==COMMIT_MSG==

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Description

Use vectorized indexOf to improve query parameter parsing and reduce allocation overhead.

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[Copilot]

Pull Request Overview

This PR optimizes query parameter parsing in DialogueFeignClient.FeignEndpoint#renderPath to improve performance in high-throughput RPC scenarios. The optimization replaces Guava's Splitter with vectorized indexOf operations to reduce allocation overhead and improve parsing efficiency.

• Replaces QUERY_VALUE_SPLITTER with direct indexOf operations for key=value parsing
• Adds comprehensive test coverage for query parameter edge cases including empty values and malformed parameters
• Maintains existing error handling behavior while improving performance

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
DialogueFeignClient.java	Replaces Guava Splitter with direct string operations for query parameter parsing
JaxRsClientDialogueEndpointTest.java	Adds test coverage for query parameter parsing edge cases and error conditions

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[Copilot]

The condition equalsIndex > 0 excludes valid query parameters that start with '=' (empty key). Based on the test cases, it appears '=' should be handled as a valid parameter with empty key and empty value. The condition should be equalsIndex >= 0 to handle this case.

Suggested change

	if (equalsIndex > 0) {
	if (equalsIndex >= 0) {

[pkoenig10]

We probably want to ensure that there aren't more than 2 segments.

[pkoenig10]

nit: I'd prefer if we wrote this as if-throw to avoid additional nesting in the non-exceptional case.