public ShenyuPluginChain getChain() {
            return chain;
        }
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 argumentId the argument id {@linkplain #getArgumentId}
@return {@code Mono<Void>} to indicate when request handling is complete
shenyu-plugin/shenyu-plugin-wasm-api/src/main/java/org/apache/shenyu/plugin/wasm/api/AbstractWasmPlugin.java