Steps to reproduce:
1. Launch Microsoft DocumentDB Emulator
2. Open attached project
3. Open "Test" scene
4. Enter play mode

Expected result: DocumentClient is successfully initialized
Actual result: "TypeLoadException: Could not resolve type with token 010000ef" exception is thrown

Reproducible with: 2017.1.0b1, 2017.1.0b4

Full error: TypeLoadException: Could not resolve type with token 010000ef
Microsoft.Azure.Documents.Client.DocumentClient.Initialize (System.Uri serviceEndpoint, Microsoft.Azure.Documents.Client.ConnectionPolicy connectionPolicy, System.Nullable`1[T] desiredConsistencyLevel) (at <b9b982171e474c22901ba295dc40b815>:0)
Microsoft.Azure.Documents.Client.DocumentClient..ctor (System.Uri serviceEndpoint, System.String authKeyOrResourceToken, Microsoft.Azure.Documents.Client.ConnectionPolicy connectionPolicy, System.Nullable`1[T] desiredConsistencyLevel) (at <b9b982171e474c22901ba295dc40b815>:0)
DocDb.DbConnection.Awake () (at Assets/Plugins/DocDb/DbConnection.cs:16)

Update: We've filed an issue upstream with Xamarin for this https://github.com/mono/mono/issues/7410