C# — Message Types

Message types for control-plane and data-plane operations. All message classes are in Nnrp.Core.

Import

using Nnrp.Core;

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Handshake Messages

ClientHelloMessage

Property	Type	Description
SessionId	uint	Client-assigned session ID
MaxViews	int	Max concurrent views
EnableCache	bool	Enable server-side cache
PayloadKindMask	PayloadKind	Supported payload type mask
AuthBlock	ReadOnlyMemory<byte>	Auth block (application-defined)
Extensions	IReadOnlyList<ControlExtensionEntry>	Extension entries

public static ClientHelloMessage Parse(NnrpFramedMessage msg);
public NnrpFramedMessage Build();

ServerHelloAckMessage

Property	Type	Description
SessionId	uint	Server-confirmed session ID
TransportId	TransportId	Selected transport
EnableCache	bool	Cache enabled
MaxCacheEntries	int	Max cache entries
MaxCacheBytes	long	Max cache bytes
PayloadKindMask	PayloadKind	Server supported payload types
Extensions	IReadOnlyList<ControlExtensionEntry>	Extension entries

public static ServerHelloAckMessage Parse(NnrpFramedMessage msg);
public NnrpFramedMessage Build();

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Session Management Messages

SessionPatchMessage

Property	Type	Description
PatchFields	SessionPatchField	Fields to update
TargetCadence	int	Target frame rate
QualityTier	int	Quality tier
ActiveLaneMask	uint	Active view mask
PreferredCodec	int	Preferred codec ID
PreferredCompression	int	Preferred compression level

public static SessionPatchMessage Parse(NnrpFramedMessage msg);
public NnrpFramedMessage Build(uint sessionId);

SessionPatchAckMessage

Property	Type	Description
PatchFields	SessionPatchField	Successfully applied fields
Status	SessionPatchAckStatus	Application result
RejectReason	SessionPatchRejectReason	Reject reason (valid when Status is Rejected)

public static SessionPatchAckMessage Parse(NnrpFramedMessage msg);
public NnrpFramedMessage Build(uint sessionId);

CloseMessage

public static CloseMessage Parse(NnrpFramedMessage msg);
public NnrpFramedMessage Build(uint sessionId, HeaderFlags flags = HeaderFlags.None);

ErrorMessage

Property	Type	Description
ErrorCode	ErrorCode	Error code
ErrorScope	ErrorScope	Error scope
FrameId	uint	Related frame ID

public static ErrorMessage Parse(NnrpFramedMessage msg);
public NnrpFramedMessage Build(uint sessionId);
public static NnrpFramedMessage BuildFrom(NnrpProtocolFailure failure);

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Data-plane Messages

FrameSubmitMessage

Property	Type	Description
InputProfile	InputProfile	Input data format
SubmitMode	SubmitMode	Submission mode
BudgetPolicy	BudgetPolicy	Allowed degradation
PayloadKindBitmap	PayloadKind	Payload type bitmask
TileCount	int	Total tile count
SectionCount	int	Tensor section count
InferenceBudgetMs	int	Max inference budget (ms)
DeadlineMs	long	Absolute deadline
BodyBytes	ReadOnlyMemory<byte>	Raw body bytes

public static FrameSubmitMessage Parse(NnrpFramedMessage msg);
public NnrpFramedMessage Build(uint sessionId, uint frameId);

FrameCancelMessage

public static FrameCancelMessage Parse(NnrpFramedMessage msg);
public NnrpFramedMessage Build(uint sessionId, uint frameId);

ResultPushMessage

Property	Type	Description
ResultClass	ResultClass	Result completeness class
ResultFlags	ResultFlags	Result flags
AppliedBudgetPolicy	BudgetPolicy	Applied degradation policy
ActiveProfileId	int	Inference profile ID used
InferenceMs	int	Inference time (ms)
QueueMs	int	Queue wait time (ms)
ServerTotalMs	int	Total server time (ms)
StatusCode	int	Status code
TileIndexMode	TileIndexMode	Tile index encoding
CoveredTileCount	int	Covered tile count
DroppedTileCount	int	Dropped tile count
ReusedFrameId	uint	Reused frame ID
PayloadKindBitmap	PayloadKind	Actual payload types present
BodyBytes	ReadOnlyMemory<byte>	Raw result body

public static ResultPushMessage Parse(NnrpFramedMessage msg);
public NnrpFramedMessage Build(uint sessionId, uint frameId);

ResultDropMessage

public static ResultDropMessage Parse(NnrpFramedMessage msg);
public NnrpFramedMessage Build(uint sessionId, uint frameId);

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Cache Messages

CachePutMessage

Property	Type	Description
Key	NnrpCacheKey	Cache object key
Flags	CachePutFlags	Put flags (Pinned, Reusable)
ObjectBytes	ReadOnlyMemory<byte>	Cache object data

public static CachePutMessage Parse(NnrpFramedMessage msg);
public NnrpFramedMessage Build(uint sessionId);

CacheAckMessage

Property	Type	Description
Key	NnrpCacheKey	Cache object key
Status	CacheAckStatus	Store result

public static CacheAckMessage Parse(NnrpFramedMessage msg);
public NnrpFramedMessage Build(uint sessionId);

CacheInvalidateMessage

Property	Type	Description
Scope	CacheInvalidateScope	Invalidation scope
Key	NnrpCacheKey	Target key (valid for Single scope)
Kind	CacheObjectKind	Target kind (valid for ByKind scope)

public static CacheInvalidateMessage Parse(NnrpFramedMessage msg);
public NnrpFramedMessage Build(uint sessionId);

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Flow Control Messages

FlowUpdateMessage

Property	Type	Description
ScopeKind	FlowUpdateScopeKind	Update scope
UpdateReason	FlowUpdateReason	Update reason
BackpressureLevel	FlowUpdateBackpressureLevel	Backpressure level
ConnectionCredit	int	Connection-level credit delta
SessionCredit	int	Session-level credit delta
OperationCredit	int	Operation-level credit delta
OperationId	uint	Target operation ID
RetryAfterMs	int	Suggested retry delay (ms)
CreditEpoch	uint	Credit epoch
Flags	FlowUpdateFlags	Flow update flags

public static FlowUpdateMessage Parse(NnrpFramedMessage msg);
public NnrpFramedMessage Build(uint sessionId);

ResultHintMessage

Property	Type	Description
BudgetPolicy	ResultHintBudgetPolicy	Suggested budget policy
CongestionState	ResultHintCongestionState	Current congestion state
Reason	ResultHintReason	Hint reason
FrameId	uint	Related frame ID
QueueDepth	int	Current queue depth
EstimatedWaitMs	int	Estimated wait (ms)

public static ResultHintMessage Parse(NnrpFramedMessage msg);
public NnrpFramedMessage Build(uint sessionId);

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Control Extension Type

ControlExtensionEntry

public readonly struct ControlExtensionEntry
{
    public ushort TypeId { get; }
    public ControlExtensionFlags Flags { get; }
    public ReadOnlyMemory<byte> Payload { get; }
}

Built-in extension types: ClientHelloTransportPolicyExtension, ServerHelloAckTransportPolicyExtension, ClientHelloLossToleranceExtension, ServerHelloAckLossToleranceExtension, ClientHelloPayloadCapabilitiesExtension, ServerHelloAckPayloadCapabilitiesExtension.

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Typical Use Cases

Building a FRAME_SUBMIT packet (low-level)

var metadata = new FrameSubmitMetadata
{
    FrameId           = 42,
    InputProfile      = InputProfile.ChangedTilesLuma,
    SubmitMode        = SubmitMode.Inline,
    BudgetPolicy      = BudgetPolicy.AllowPartial,
    InferenceBudgetMs = 8,
    TileIds           = new ushort[] { 3, 7, 12 },
};
var packet = NnrpMessageBuilder.BuildFrameSubmit(
    sessionId: 42, metadata: metadata, sections: new[] { tensorSection });
await transport.SendAsync(packet.Pack());

Parsing control extensions

var entries = ControlExtensionParser.Unpack(packet.Metadata);
foreach (var entry in entries)
{
    if (entry.TypeId == NnrpExtensionTypeIds.ClientHelloTransportPolicy)
    {
        var ext = ClientHelloTransportPolicyExtension.Unpack(entry.Payload.Span);
        Console.WriteLine("Requested policy: " + ext.Policy);
    }
}

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Common Pitfalls

WARNING

1. Metadata vs Body: NnrpPacket.Metadata contains small structured fields; NnrpPacket.Body contains large binary payloads. Do not call Tensor unpack on Metadata.

2. TileIds and TilePayloads must be index-aligned. Mismatched order causes tile reconstruction errors.

3. ReadOnlyMemory<byte> slices from a pooled packet share lifetime with the packet. If the packet is returned to the pool before you finish reading the slice, you will read garbage data.