OPC UA monitored item with structure|OPC UA Implementation: Stacks, Tools, and Samples|Forum|OPC Foundation

Hello

I monitor a structure on my server with the MonitoredItem mode offered by OPC-UA (https://reference.opcfoundation.org/v104/Core/docs/Part4/5.12.1/). In general this workes fine. 
If I change the structure on the server the change is submitted to the client. The question that arises is, if I change the value of just one member
of the structure, is the server then sending the whole structure? 

Since we are using quite large structures this would end up in an perfomance issues.

I tried to understand with Wireshark whether only one member is sent or the entire structure. 
Unfortunately, I cannot derive from the OPC Binary Protocol what is exactly being sent. There might be some help here too

Excerpt from wireshark

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OpcUa Binary Protocol
Message Type: MSG
Chunk Type: F
Message Size: 85
SecureChannelId: 2225294284
Security Token Id: 2
Security Sequence Number: 606
Security RequestId: 554
OpcUa Service : Encodeable Object
TypeId : ExpandedNodeId
NodeId EncodingMask: Four byte encoded Numeric (0x01)
NodeId Namespace Index: 0
NodeId Identifier Numeric: PublishResponse (829)
PublishResponse
ResponseHeader: ResponseHeader
Timestamp: May 12, 2000 08:54:06.602000000 Mitteleuropäische Sommerzeit
RequestHandle: 553
ServiceResult: 0x00000000 [Good]
ServiceDiagnostics: DiagnosticInfo
EncodingMask: 0x00
.... ...0 = has symbolic id: False
.... ..0. = has namespace: False
.... .0.. = has localizedtext: False
.... 0... = has locale: False
...0 .... = has additional info: False
..0. .... = has inner statuscode: False
.0.. .... = has inner diagnostic info: False
StringTable: Array of String
ArraySize: 0
AdditionalHeader: ExtensionObject
TypeId: ExpandedNodeId
EncodingMask: 0x00, EncodingMask: Two byte encoded Numeric
.... 0000 = EncodingMask: Two byte encoded Numeric (0x0)
.0.. .... = has server index: False
0... .... = has namespace uri: False
Identifier Numeric: 0
EncodingMask: 0x00
.... ...0 = has binary body: False
.... ..0. = has xml body: False
SubscriptionId: 1827064279
AvailableSequenceNumbers: Array of UInt32
ArraySize: 0
MoreNotifications: False
NotificationMessage: NotificationMessage
SequenceNumber: 21
PublishTime: May 12, 2000 08:54:06.602000000 Mitteleuropäische Sommerzeit
NotificationData: Array of ExtensionObject
ArraySize: 0
Results: Array of StatusCode
ArraySize: 0
DiagnosticInfos: Array of DiagnosticInfo

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Thanks in advance

Kind Regards