How Logback outputs logs to Kafka configuration example

<dependency>
      <groupId></groupId>
      <artifactId>logback-kafka-appender</artifactId>
      <version>0.2.0-RC2</version>
    </dependency>
    <dependency>
      <groupId></groupId>
      <artifactId>logstash-logback-encoder</artifactId>
      <version>6.4</version>
    </dependency>
    <dependency>
      <groupId></groupId>
      <artifactId>logback-classic</artifactId>
      <version>1.2.3</version>
    </dependency>

<springProperty scope="context" name="service" source="" defaultValue="UnknownService"/>
    <springProperty scope="context" name="env" source="" defaultValue="test"/>
    <springProperty scope="context" name="bootstrapServers" source="" defaultValue="localhost:9092"/>
    <!--The above three lines require theymlcorrespond-->
    <appender name="kafkaAppender" class="">
        <encoder class="">
            <providers class="">
                <pattern>
                    <pattern>
                        {
                        "env": "${env}",
                        "service":"${service}",
                        "date":"%d{yyyy-MM-dd HH:mm:}",
                        "level":"%level",
                        "thread": "%thread",
                        "logger": "%logger{36}",
                        "msg":"%msg",
                        "exception":"%exception"
                        }
                    </pattern>
                </pattern>
            </providers>
        </encoder>
        <topic>msa-log-${env}</topic>
        <keyingStrategy class=""/>
        <deliveryStrategy class=""/>
        <producerConfig>acks=0</producerConfig>
        <producerConfig>=1000</producerConfig>
        <producerConfig>=0</producerConfig>
        <producerConfig>=${bootstrapServers}</producerConfig>
    </appender>
    <appender name="ASYNC" class="">
        <appender-ref ref="kafkaAppender"/>
    </appender>
    <root level="INFO">
        <appender-ref ref="ASYNC"/>
    </root>