adding size

Author: sdelamo

mcp-core/src/main/java/io/modelcontextprotocol/server/servlet/HttpServletRequestMcpTransportContextExtractor.java

@@ -28,7 +28,7 @@ public McpTransportContext extract(HttpServletRequest request) {
 	 * @return Extracts Map for MCP Transport Context
 	 */
 	protected Map<String, Object> metadata(HttpServletRequest request) {
-		Map<String, Object> metadata = new HashMap<>();
+		Map<String, Object> metadata = new HashMap<>(3);
 		metadata.put(io.modelcontextprotocol.spec.HttpHeaders.PROTOCOL_VERSION,
 				Optional.ofNullable(request.getHeader(io.modelcontextprotocol.spec.HttpHeaders.PROTOCOL_VERSION))
 					.orElse(ProtocolVersions.MCP_2025_03_26));