update BaseXapClient

core/src/main/kotlin/com/expediagroup/sdk/core/client/BaseXapClient.kt

@@ -23,6 +23,7 @@ import com.expediagroup.sdk.core.plugin.authentication.strategy.AuthenticationSt
 import io.ktor.client.HttpClient
 import io.ktor.client.engine.HttpClientEngine
 import io.ktor.client.engine.okhttp.*
+import okhttp3.OkHttpClient
 
 /**
  * The integration point between the SDK Core and the product SDKs.
@@ -62,4 +63,20 @@ abstract class BaseXapClient(
     /** A [BaseXapClient] builder. */
     @Suppress("unused", "UnnecessaryAbstractClass") // This is used by the generated SDK clients.
     abstract class Builder<SELF : Builder<SELF>> : HttpConfigurableBuilder<SELF>()
+
+    /** A [BaseXapClient] builder with ability to pass a custom okhttp client. */
+    @Suppress("unused", "UnnecessaryAbstractClass") // This is used by the generated SDK clients.
+    abstract class BuilderWithHttpClient<SELF : Client.Builder<SELF>> : Client.Builder<SELF>() {
+        protected var okHttpClient: OkHttpClient? = null
+
+        @Suppress("UNCHECKED_CAST")
+        override fun self(): SELF = this as SELF
+
+        /** Sets the [OkHttpClient] to use for the [BaseXapClient]. */
+        fun okHttpClient(okHttpClient: OkHttpClient): SELF {
+            this.okHttpClient = okHttpClient
+            return self()
+        }
+
+    }
 }