如何使用kotlin向sendgrid API发出请求

dependencies {
    implementation 'org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.5.31'
    implementation 'com.squareup.okhttp3:okhttp:4.9.1'
}

import okhttp3.MediaType.Companion.toMediaType
import okhttp3.OkHttpClient
import okhttp3.Request
import okhttp3.RequestBody.Companion.toRequestBody

fun sendEmail() {
    val client = OkHttpClient()
    val apiKey = "YOUR_SENDGRID_API_KEY"
    val url = "https://api.sendgrid.com/v3/mail/send"
    
    val json = """
        {
            "personalizations": [
                {
                    "to": [
                        {
                            "email": "recipient@example.com"
                        }
                    ]
                }
            ],
            "from": {
                "email": "sender@example.com"
            },
            "subject": "Hello, SendGrid!",
            "content": [
                {
                    "type": "text/plain",
                    "value": "This is a test email sent using SendGrid API."
                }
            ]
        }
    """.trimIndent()
    
    val mediaType = "application/json".toMediaType()
    val requestBody = json.toRequestBody(mediaType)
    
    val request = Request.Builder()
        .url(url)
        .addHeader("Authorization", "Bearer $apiKey")
        .post(requestBody)
        .build()
    
    val response = client.newCall(request).execute()
    val responseBody = response.body?.string()
    
    println(responseBody)
}