特性调整

• Kotlin 1.4.0 & Kotlinx Coroutines 1.3.9
• Kotlinx Serialization 1.0.0-RC： 不兼容之前版本，且Kotlin版本需为1.4.0+
• RSocket http gateway uses "/api" as prefix to route RSocket services

Bug修复

• 修复RSocket Channel通讯时switchOnFirst的bug
• 修复example中alibaba-rsocket-core依赖错误

文档

• Alibaba RSocket Broker Example Docs: https://github.com/linux-china/alibaba-broker-example-parent/tree/master/book/src