我想将一个Android-Kotlin项目转换为React Native，但遇到了一个问题：
Kotlin项目处理从API获取数据的方式如下：

import java.net.URL
import java.nio.ByteBuffer
import java.nio.ByteOrder

fun getData() {

    val bytes = try {
        URL(address).readBytes()
    } catch (e: Exception) {
        return emptySet()
    }

    val arrayBuffer = ByteBuffer
        .wrap(bytes)
        .order(ByteOrder.BIG_ENDIAN)
    }

    return arrayBuffer
}

fun URL.readBytes(settings: HeaderSetter? = null): ByteArray {
    val request = Request.Builder()
        .url(this).let {
            settings?.invoke(it) ?: it
        }.build()

    return client.newCall(request).execute().also { if (it.code() != 200) throw IOException("CODE ${it.code()}") }.body()?.use { it.bytes() } ?: throw IOException()
}

var clientHolder: OkHttpClient? = null
val client: OkHttpClient
    get() = clientHolder ?: clientBuilder.build().also {
        clientHolder = it
    }

我在反动派里是怎么做的？