# IOpcServiceRequestHeader Members

> Reference: Defines an interface which provides the common parameters of the request of a service, as defined by the RequestHeader of OPC UA.

<dl class="api-definition">
<dt>Type</dt>
<dd><a href="./">IOpcServiceRequestHeader</a></dd>
<dt>Namespace</dt>
<dd><a href="../namespaces/opc.uafx.services">Opc.UaFx.Services</a></dd>
<dt>Assembly</dt>
<dd>Opc.UaFx.Advanced.dll</dd>
<dt>Package</dt>
<dd>Opc.UaFx.Advanced v2.59.0</dd>
<dt>Also in</dt>
<dd>Opc.UaFx.Client</dd>
</dl>

## Properties

### TimeoutHint

Gets or sets the time in milliseconds after which the request is to be cancelled.

<div class="api-signature" data-lang="csharp">

```csharp
long TimeoutHint { get; set; }
```

</div>

<div class="api-signature" data-lang="vbnet">

```vbnet
Property TimeoutHint As Long
```

</div>

**Property value**

[Int64](https://learn.microsoft.com/dotnet/api/system.int64)

The timeout of the request in milliseconds, or 0 for no timeout.

### Timestamp

Gets or sets the time the request has been sent.

<div class="api-signature" data-lang="csharp">

```csharp
DateTime Timestamp { get; set; }
```

</div>

<div class="api-signature" data-lang="vbnet">

```vbnet
Property Timestamp As Date
```

</div>

**Property value**

[DateTime](https://learn.microsoft.com/dotnet/api/system.datetime)

The time the client sent the request.