fun X509Certificate.sha256Hash(): ByteString = publicKey.encoded.toByteString().sha256()

    /**
     * Returns the SHA-256 of `certificate`'s public key.
     *
     * In OkHttp 3.1.2 and earlier, this returned a SHA-1 hash of the public key. Both types are
     * supported, but SHA-256 is preferred.
     */
    @JvmStatic
    fun pin(certificate: Certificate): String {

 * TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384
 * TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
 * TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256
 * TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256
 * TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA[²][http2_naughty]
 * TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA[²][http2_naughty]
 * TLS_RSA_WITH_AES_128_GCM_SHA256[²][http2_naughty]
 * TLS_RSA_WITH_AES_256_GCM_SHA384[²][http2_naughty]

TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384
TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256
TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256
TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
TLS_RSA_WITH_AES_128_GCM_SHA256
TLS_RSA_WITH_AES_256_GCM_SHA384
TLS_RSA_WITH_AES_128_CBC_SHA

TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384
TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256
TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256
TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
TLS_RSA_WITH_AES_128_GCM_SHA256
TLS_RSA_WITH_AES_256_GCM_SHA384
TLS_RSA_WITH_AES_128_CBC_SHA

TLS_AES_128_GCM_SHA256
TLS_AES_256_GCM_SHA384
TLS_CHACHA20_POLY1305_SHA256
TLS_AES_128_CCM_SHA256
TLS_AES_256_CCM_8_SHA256
TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384
TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256
TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA

import java.security.Security
import okhttp3.internal.platform.Platform
import org.conscrypt.Conscrypt

// TLS 1.3
private val TLS13_CIPHER_SUITES =
  listOf(
    CipherSuite.TLS_AES_128_GCM_SHA256,
    CipherSuite.TLS_AES_256_GCM_SHA384,
    CipherSuite.TLS_CHACHA20_POLY1305_SHA256,
    CipherSuite.TLS_AES_128_CCM_SHA256,
    CipherSuite.TLS_AES_128_CCM_8_SHA256,
  )

/**
 * A TLS 1.3 only Connection Spec. This will be eventually be exposed

	public static final field TLS_DHE_DSS_WITH_AES_256_CBC_SHA Lokhttp3/CipherSuite;
	public static final field TLS_DHE_DSS_WITH_AES_256_CBC_SHA256 Lokhttp3/CipherSuite;
	public static final field TLS_DHE_DSS_WITH_AES_256_GCM_SHA384 Lokhttp3/CipherSuite;
	public static final field TLS_DHE_DSS_WITH_CAMELLIA_128_CBC_SHA Lokhttp3/CipherSuite;
	public static final field TLS_DHE_DSS_WITH_CAMELLIA_256_CBC_SHA Lokhttp3/CipherSuite;

        CipherSuite.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
        CipherSuite.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
        CipherSuite.TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
        CipherSuite.TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384);
    final ConnectionSpec spec = new ConnectionSpec.Builder(ConnectionSpec.MODERN_TLS)
        .cipherSuites(customCipherSuites.toArray(new CipherSuite[0]))
        .build();

          "maxIntermediateCas < 0: $maxIntermediateCas"
        }
        this.maxIntermediateCas = maxIntermediateCas
      }

    /**
     * Configure the certificate to generate a 256-bit ECDSA key, which provides about 128 bits of
     * security. ECDSA keys are noticeably faster than RSA keys.
     *
     * This is the default configuration and has been since this API was introduced in OkHttp

            for (i in 0 until n) {
              sink.writeByte('x'.code)
            }
          } else {
            val buf = ByteArray(if (writeKind == WriteKind.SMALL_BUFFERS) 256 else 64 * 1024)
            Arrays.fill(buf, 'x'.code.toByte())
            var i = 0
            while (i < n) {
              sink.write(buf, 0, Math.min(buf.size, n - i))
              i += buf.size
            }