Read file content using recursion with Kotlin

Functions.kt

fun readFileContent(file: File) : String {
    val reader = FileReader(file)

    fun readBuffer(bufferedReader: BufferedReader) : String {
        val result = StringBuilder()

        fun finally() : String {
            bufferedReader.close()
            return result.toString()
        }

        tailrec fun readLine() : String {
            val line = bufferedReader.readLine() ?: return finally()

            result.append(line).append("\n")

            return readLine()
        }

        return readLine()
    }

    return readBuffer(BufferedReader(reader))
}