Kotlin fetch API

SendRequest.kt

import java.net.HttpURLConnection
import java.net.URL

/**
 * Sends an HTTP request to the given [url], using the given HTTP [method]. The request can also
 * include custom [headers] and [body].
 * 
 * Returns the [Response] object containing [statusCode][Response.statusCode],
 * [headers][Response.headers] and [body][Response.body].
 */
fun sendRequest(url: String, method: String = "GET", headers: Map<String, String>? = null, body: String? = null): Response {
    val conn = URL(url).openConnection() as HttpURLConnection

    with(conn) {
        requestMethod = method
        doOutput = body != null
        headers?.forEach(this::setRequestProperty)
    }

    if (body != null) {
        conn.outputStream.use {
            it.write(body.toByteArray())
        }
    }

    val responseBody = conn.inputStream.use { it.readBytes() }.toString(Charsets.UTF_8)

    return Response(conn.responseCode, conn.headerFields, responseBody)
}

data class Response(val statusCode: Int, val headers: Map<String, List<String>>? = null, val body: String? = null)

zexamples.kt

//
// Obtaining data via GET request
//
val response = sendRequest(
    url = "https://jsonplaceholder.typicode.com/posts/1"
)
println(response.statusCode)
println(response.headers)
println(response.body)

//
// Updating data via POST request
//
sendRequest(
    url = "https://jsonplaceholder.typicode.com/posts/1",
    method = "POST",
    headers = mapOf(
        "Content-Type" to "application/json"
    ),
    body = """{ "title": "Sample title", "body": "Sample body" }"""
)

getting Error : java.io.FileNotFoundException: {my server url}, is there any possibility that it's throwing error in the process of reading or writing the stream? @GrzegorzDyrda