Add inflight request gauge

docs

@@ -1 +1 @@
-Subproject commit f37b981f1b0dfb1ea4020e509180840a15a7289a
+Subproject commit 7fc41dd5738ab4c9dbc2e756e8140719ce2c2d1c

psalm-baseline.xml

@@ -3643,6 +3643,12 @@
       <code><![CDATA[$request->getSent()]]></code>
       <code><![CDATA[$request->getSent()]]></code>
     </PossiblyNullOperand>
+    <PossiblyNullReference>
+      <code><![CDATA[dec]]></code>
+      <code><![CDATA[dec]]></code>
+      <code><![CDATA[observe]]></code>
+      <code><![CDATA[observe]]></code>
+    </PossiblyNullReference>
     <RedundantConditionGivenDocblockType>
       <code><![CDATA[$this->API->authorized_dc == $this->datacenter && $this->API->authorized === \danog\MadelineProto\API::LOGGED_IN]]></code>
     </RedundantConditionGivenDocblockType>

schemas

@@ -1 +1 @@
-Subproject commit 6fc533efe6e1ce440f6da4b0d7037460f73ce96b
+Subproject commit da7d066eee5fa53e5ef43a964032d56197810de9

src/Loop/Connection/WriteLoop.php

@@ -125,6 +125,11 @@ final class WriteLoop extends Loop
                 $this->connection->outgoing_messages[$message_id] = $message;
                 $this->connection->new_outgoing[$message_id] = $message;
 
+                if ($message->getSent() === null) {
+                    $this->connection->inFlightGauge?->inc([
+                        'method' => $message->constructor,
+                    ]);
+                }
                 $message->sent();
             }
             if ($skipped_all) {
@@ -371,6 +376,11 @@ final class WriteLoop extends Loop
                 if ($message->hasPromise()) {
                     $this->connection->new_outgoing[$message_id] = $message;
                 }
+                if ($message->getSent() === null) {
+                    $this->connection->inFlightGauge?->inc([
+                        'method' => $message->constructor,
+                    ]);
+                }
                 $message->sent();
                 $message->cancellation?->subscribe(function () use ($message): void {
                     if ($message->hasMsgId()) {

src/MTProtoSession/ResponseHandler.php

@@ -281,8 +281,11 @@ trait ResponseHandler
                 'error_message' => 'OK',
                 'error_code' => '200',
             ]);
-            $this->requestLatencies?->observe(
+            $this->inFlightGauge->dec([
-                (hrtime(true) - $request->getSent()) / 1_000_000_000.0,
+                'method' => $request->constructor,
+            ]);
+            $this->requestLatencies->observe(
+                hrtime(true) - $request->getSent(),
                 ['method' => $request->constructor]
             );
         }
@@ -301,8 +304,11 @@ trait ResponseHandler
                 'error_message' => preg_replace('/\d+/', 'X', $response['error_message']),
                 'error_code' => (string) $response['error_code'],
             ]);
-            $this->requestLatencies?->observe(
+            $this->inFlightGauge->dec([
-                (hrtime(true) - $request->getSent()) / 1_000_000_000.0,
+                'method' => $request->constructor,
+            ]);
+            $this->requestLatencies->observe(
+                hrtime(true) - $request->getSent(),
                 ['method' => $request->constructor]
             );
         }

src/MTProtoSession/Session.php

@@ -44,6 +44,7 @@ trait Session
     use CallHandler;
     use Reliable;
     public ?BetterGauge $pendingOutgoingGauge = null;
+    public ?BetterGauge $inFlightGauge = null;
     public ?BetterCounter $incomingCtr = null;
     public ?BetterCounter $outgoingCtr = null;
     public ?BetterCounter $incomingBytesCtr = null;
@@ -185,12 +186,34 @@ trait Session
     {
         $labels = ['datacenter' => (string) $this->datacenter, 'connection' => (string) $this->id];
         $this->pendingOutgoingGauge = $this->API->getPromGauge("MadelineProto", "pending_outgoing_mtproto_messages", "Number of not-yet sent outgoing MTProto messages", $labels);
+        $this->inFlightGauge = $this->API->getPromGauge("MadelineProto", "inflight_requests", "Number of in-flight requests", $labels);
         $this->incomingCtr = $this->API->getPromCounter("MadelineProto", "incoming_mtproto_messages", "Number of received MTProto messages", $labels);
         $this->outgoingCtr = $this->API->getPromCounter("MadelineProto", "outgoing_mtproto_messages", "Number of sent MTProto messages", $labels);
         $this->incomingBytesCtr = $this->API->getPromCounter("MadelineProto", "incoming_bytes", "Number of received bytes", $labels);
         $this->outgoingBytesCtr = $this->API->getPromCounter("MadelineProto", "outgoing_bytes", "Number of sent bytes", $labels);
         $this->requestResponse = $this->API->getPromCounter("MadelineProto", "request_responses", "Received RPC error or success status of requests by method.", $labels);
-        $this->requestLatencies = $this->API->getPromHistogram("MadelineProto", "request_latencies", "Request latency by method", $labels);
+        $this->requestLatencies = $this->API->getPromHistogram(
+            "MadelineProto",
+            "request_latencies",
+            "Request latency in nanoseconds by method",
+            $labels,
+            [
+                5_000_000,
+                10_000_000,
+                25_000_000,
+                50_000_000,
+                75_000_000,
+                100_000_000,
+                250_000_000,
+                500_000_000,
+                750_000_000,
+                1000_000_000,
+                2500_000_000,
+                5000_000_000,
+                7500_000_000,
+                10000_000_000,
+            ]
+        );
         if ($this->session_id === null) {
             $this->resetSession("creating initial session");
         }