@Override
    public String toString() {
        return MoreObjects.toStringHelper(this)
                          .add("preprocessors", preprocessors)
                          .add("rpcPreprocessors", rpcPreprocessors)
                          .toString();
    }
Decorates the specified {@link RpcPreClient} using preprocessors.

@param execution the {@link RpcPreClient} being decorated
core/src/main/java/com/linecorp/armeria/client/ClientPreprocessors.java