Internal: Few memory allocation optimizations on the point-read hot-path

[FabianMeiswinkel]

No description provided.

[Copilot]

Pull Request Overview

This PR introduces memory allocation optimizations on the point-read hot-path by adjusting builder expected sizes and streamlining header and URI handling.

• Adjusts the expected size for map builders in response headers and diagnostics snapshots
• Introduces shared empty URI constants and conditional replica path initialization in request arguments
• Refines default header handling in ThinClientStoreModel and RxGatewayStoreModel while correcting a typo in an error message

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
RntbdResponseHeaders.java	Adjusts builder expected size for map construction
RntbdRequestArgs.java	Introduces emptyUri and emptyUriPath constants with conditional replicaPath initialization
UserAgentContainer.java	Adds BASE_USER_AGENT_STRING constant for fallback user-agent value
ThinClientStoreModel.java	Utilizes precomputed defaultHeaders and removes a redundant null check on request properties
RxGatewayStoreModel.java	Uses a HashMap with an initial capacity and improves user-agent header handling; fixes error message typo
CosmosDiagnosticsSystemUsageSnapshot.java	Updates builder expected size for creating immutable maps

Comments suppressed due to low confidence (2)

sdk/cosmos/azure-cosmos/src/main/java/com/azure/cosmos/implementation/RxGatewayStoreModel.java:121

• Correct the typo in the error message: 'userAGentContainer' should be 'userAgentContainer'.

checkNotNull(userAgentContainer, "Argument 'userAGentContainer' must not be null.");

sdk/cosmos/azure-cosmos/src/main/java/com/azure/cosmos/implementation/ThinClientStoreModel.java:125

• The null check and initialization of request.properties has been removed; please confirm that request.properties is guaranteed to be initialized elsewhere to avoid potential null pointer issues.

if (request.properties == null) { request.properties = new HashMap<>(); }