uniloadMultipart

suspend fun <ERROR CLASS>.uniloadMultipart(    onFormItem: (<ERROR CLASS>) -> Unit = {},     onCustomFileItem: (<ERROR CLASS>) -> Unit = {},     onBinaryContent: (<ERROR CLASS>) -> Unit = {}): <ERROR CLASS>
suspend fun <T> <ERROR CLASS>.uniloadMultipart(    deserializer: <ERROR CLASS><T>,     onFormItem: (<ERROR CLASS>) -> Unit = {},     onCustomFileItem: (<ERROR CLASS>) -> Unit = {},     onBinaryContent: (<ERROR CLASS>) -> Unit = {}): Pair<<ERROR CLASS>, T>