diff --git a/src/conduit/ConduitClient.php b/src/conduit/ConduitClient.php
--- a/src/conduit/ConduitClient.php
+++ b/src/conduit/ConduitClient.php
@@ -155,12 +155,8 @@
         $this->password);
     }
 
-    $conduit_future = new ConduitFuture($core_future);
-    $conduit_future->setClient($this, $method);
-    $conduit_future->beginProfile($data);
-    $conduit_future->isReady();
-
-    return $conduit_future;
+    return id(new ConduitFuture($core_future))
+      ->setClient($this, $method);
   }
 
   public function setBasicAuthCredentials($username, $password) {
diff --git a/src/conduit/ConduitFuture.php b/src/conduit/ConduitFuture.php
--- a/src/conduit/ConduitFuture.php
+++ b/src/conduit/ConduitFuture.php
@@ -2,8 +2,8 @@
 
 final class ConduitFuture extends FutureProxy {
 
-  protected $client;
-  protected $conduitMethod;
+  private $client;
+  private $conduitMethod;
   private $profilerCallID;
 
   public function setClient(ConduitClient $client, $method) {
@@ -12,15 +12,19 @@
     return $this;
   }
 
-  public function beginProfile($data) {
-    $profiler = PhutilServiceProfiler::getInstance();
-    $this->profilerCallID = $profiler->beginServiceCall(
-      array(
-        'type'    => 'conduit',
-        'method'  => $this->conduitMethod,
-        'size'    => strlen(http_build_query($data, '', '&')),
-      ));
-    return $this;
+  public function isReady() {
+    if ($this->profilerCallID === null) {
+      $profiler = PhutilServiceProfiler::getInstance();
+
+      $this->profilerCallID = $profiler->beginServiceCall(
+        array(
+          'type'    => 'conduit',
+          'method'  => $this->conduitMethod,
+          'size'    => $this->getProxiedFuture()->getHTTPRequestByteLength(),
+        ));
+    }
+
+    return parent::isReady();
   }
 
   protected function didReceiveResult($result) {
diff --git a/src/future/http/BaseHTTPFuture.php b/src/future/http/BaseHTTPFuture.php
--- a/src/future/http/BaseHTTPFuture.php
+++ b/src/future/http/BaseHTTPFuture.php
@@ -264,6 +264,18 @@
     return $this->addHeader('Authorization', 'Basic '.$credentials);
   }
 
+  public function getHTTPRequestByteLength() {
+    // NOTE: This isn't very accurate, but it's only used by the "--trace"
+    // call profiler to help pick out huge requests.
+    $data = $this->getData();
+
+    if (is_scalar($data)) {
+      return strlen($data);
+    }
+
+    return strlen(http_build_query($data, '', '&'));
+  }
+
 
 /* -(  Resolving the Request  )---------------------------------------------- */