Allow custom request timeouts to be passed to OkHttp client (#86)

httpclient/src/main/kotlin/tbdex/sdk/httpclient/TbdexHttpClient.kt

@@ -17,12 +17,13 @@ import tbdex.sdk.protocol.models.Offering
 import tbdex.sdk.protocol.serialization.Json
 import tbdex.sdk.protocol.serialization.Json.jsonMapper
 import web5.sdk.dids.Did
+import java.time.Duration
 
 /**
  * A client of the tbDEX HTTP interface for communicating with a PFI.
  */
 object TbdexHttpClient {
-  private val client = OkHttpClient()
+  private var client = OkHttpClient()
   private val jsonMediaType = "application/json; charset=utf-8".toMediaType()
   private const val JSON_HEADER = "application/json"
 
@@ -180,6 +181,15 @@ object TbdexHttpClient {
     }
   }
 
+  /**
+   * Sets the timeout for all future HTTP requests
+   *
+   * @param timeout the total time to allow HTTP requests to take before they are considered timed out
+   */
+  fun setTimeout(timeout: Duration) {
+    client = OkHttpClient.Builder().callTimeout(timeout).build();
+  }
+
   /**
    * Builds an error response based on the provided HTTP response.
    *