OkHttp/Retrofit async call with lambda callback

OkHttpLambdaAsyncCallback.kt

package com.github.yamin8000.fare.model

import android.os.Bundle
import com.github.yamin8000.fare.databinding.ActivityMainBinding
import com.github.yamin8000.fare.ui.BaseActivity
import com.github.yamin8000.fare.web.Services
import com.github.yamin8000.fare.web.WEB

class MainActivity : BaseActivity() {
    
    private val binding : ActivityMainBinding by lazy(LazyThreadSafetyMode.NONE) {
        ActivityMainBinding.inflate(layoutInflater)
    }
    
    override fun onCreate(savedInstanceState : Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(binding.root)
        
        binding.text.setOnClickListener {
            val supaBase = WEB(SUPA_BASE_URL).getService(Services.StateService::class.java)
            
            supaBase.getAll().async { throwable, response ->
                if (throwable == null && response != null) {
                    Logger.d(response)
                    binding.text.text = "$response"
                }
            }
        }
    }
    
    fun <T> Call<T>.async(callback : (Throwable?, T?) -> Unit) {
        var throwable : Throwable? = null
        var result : T? = null
        this.enqueue(object : Callback<T> {
            override fun onResponse(call : Call<T>, response : Response<T>) {
                result = response.body()
                callback(throwable, result)
            }
            
            override fun onFailure(call : Call<T>, t : Throwable) {
                throwable = t
                callback(throwable, result)
            }
        })
    }
}