What's the purpose of the 'ValueType' property on IBsonSerializer, MongoDB C# driver 2.2.2
<p>I'm implementing a custom serializer by implementing the interface: IBsonSerializer defined on MongoDB C# Driver version 2.2.2.</p>

<p>The methods Serialize and Deserialize are clear, but there's a property:</p>

<p><code>Type ValueType { get; }</code> </p>

<p>The <a href="http://api.mongodb.org/csharp/2.0/html/T_MongoDB_Bson_Serialization_IBsonSerializer.htm" rel="nofollow">documentation page on mongodb.org for IBsonSerializer</a> only says:
"Gets the type of the value."
The thorough API reference on <a href="http://mongodb.github.io/mongo-csharp-driver/2.0/reference/bson/serialization/" rel="nofollow">mongodb.github.io</a> has no reference to this property at all.</p>

<p>What's the purpose of this getter?</p>