public ServerWebExchange getExchange() {
            return exchange;
        }
this is Template Method child has implements your own logic.

@param exchange   exchange the current server exchange {@linkplain ServerWebExchange}
@param chain      chain the current chain  {@linkplain ServerWebExchange}
@param selector   selector    {@linkplain SelectorData}
@param rule       rule    {@linkplain RuleData}
@param argumentId the argument id {@linkplain #getArgumentId}
@return {@code Mono<Void>} to indicate when request handling is complete
shenyu-plugin/shenyu-plugin-wasm-base/src/main/java/org/apache/shenyu/plugin/wasm/base/AbstractShenyuWasmPlugin.java