diff --git a/testtool/client/src/commonMain/kotlin/TesttoolClient.kt b/testtool/client/src/commonMain/kotlin/TesttoolClient.kt
index 2d0aed85..156806d8 100644
--- a/testtool/client/src/commonMain/kotlin/TesttoolClient.kt
+++ b/testtool/client/src/commonMain/kotlin/TesttoolClient.kt
@@ -8,7 +8,6 @@ import io.ktor.client.*
 import io.ktor.client.call.*
 import io.ktor.client.plugins.*
 import io.ktor.client.request.*
-import io.ktor.client.statement.*
 import io.ktor.http.content.*
 import kotlinx.coroutines.flow.*
 import kotlinx.io.*
@@ -44,21 +43,16 @@ private val client = HttpClient {
 
 internal suspend fun postData(path: String, bytes: ByteArray): String = client.post(path) {
     setBody(ByteArrayContent(bytes))
-}.bodyAsText()
+}.body<Source>().use { it.readString() }
 
 internal fun getData(path: String): Flow<Pair<String, ByteArray>> = flow {
-    val source = client.get(path).body<Source>()
-    try {
+    client.get(path).body<Source>().use { source ->
         while (true) {
-            val idLength = source.readInt()
+            val idLength = runCatching { source.readInt() }.getOrNull() ?: break
             val id = source.readString(idLength.toLong())
-            val contentLength = source.readLong().toInt()
+            val contentLength = source.readInt()
             val content = source.readByteArray(contentLength)
             emit(id to content)
         }
-    } catch (cause: EOFException) {
-        // ignore
-    } finally {
-        source.close()
     }
 }
diff --git a/testtool/server/src/main/kotlin/compatibility.kt b/testtool/server/src/main/kotlin/compatibility.kt
index d2a2982b..25bbae16 100644
--- a/testtool/server/src/main/kotlin/compatibility.kt
+++ b/testtool/server/src/main/kotlin/compatibility.kt
@@ -58,9 +58,11 @@ internal fun Route.routes(
 }
 
 private suspend fun ApplicationCall.saveFile(path: Path, name: String) {
-    val bytes = request.receiveChannel().readRemaining().readByteArray()
+    val buffer = request.receiveChannel().readBuffer()
 
-    path.createDirectories().resolve(name).writeBytes(bytes, StandardOpenOption.CREATE_NEW)
+    path.createDirectories().resolve(name)
+        .outputStream(StandardOpenOption.CREATE_NEW)
+        .use(buffer::readTo)
 }
 
 private suspend fun ApplicationCall.getFiles(path: Path, get: Path.() -> Pair<String, Path>) {
@@ -79,8 +81,9 @@ private suspend fun ApplicationCall.getFiles(path: Path, get: Path.() -> Pair<St
         val idBytes = id.encodeToByteArray()
         output.writeInt(idBytes.size)
         output.write(idBytes)
-        output.writeLong(contentPath.fileSize())
-        output.write(contentPath.inputStream(), contentPath.fileSize())
+        output.writeInt(contentPath.fileSize().toInt())
+        contentPath.inputStream()
+            .use(output::transferFrom)
     }
 
     respondSource(output)