Upgrade ktor to beta 4 (#4192)

frameworks/Kotlin/ktor/pom.xml

@@ -12,9 +12,9 @@
     <name>org.jetbrains.ktor tech-empower-framework-benchmark</name>
 
     <properties>
-        <kotlin.version>1.3.0-rc-190</kotlin.version>
-        <ktor.version>1.0.0-beta-1</ktor.version>
-        <serialization.runtime>0.8.3-rc13</serialization.runtime>
+        <kotlin.version>1.3.0</kotlin.version>
+        <ktor.version>1.0.0-beta-4</ktor.version>
+        <serialization.runtime>0.9.0</serialization.runtime>
 
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <hikaricp.version>3.2.0</hikaricp.version>

frameworks/Kotlin/ktor/src/main/kotlin/org/jetbrains/ktor/benchmarks/Hello.kt

@@ -2,10 +2,10 @@ package org.jetbrains.ktor.benchmarks
 
 import com.zaxxer.hikari.*
 import io.ktor.application.*
-import io.ktor.content.*
 import io.ktor.features.*
 import io.ktor.html.*
 import io.ktor.http.*
+import io.ktor.http.content.*
 import io.ktor.response.*
 import io.ktor.routing.*
 import kotlinx.coroutines.*
@@ -13,6 +13,7 @@ import kotlinx.coroutines.scheduling.*
 import kotlinx.html.*
 import kotlinx.serialization.*
 import kotlinx.serialization.json.*
+import java.util.*
 import java.util.concurrent.*
 
 @Serializable
@@ -24,6 +25,7 @@ data class World(val id: Int, var randomNumber: Int)
 @Serializable
 data class Fortune(val id: Int, var message: String)
 
+@UseExperimental(ImplicitReflectionSerializer::class, InternalCoroutinesApi::class)
 fun Application.main() {
     val worldSerializer = World.serializer()
     val worldListSerializer = World.serializer().list