Struct EnvelopeMetadata 

pub struct EnvelopeMetadata {
    pub timestamp: Option<u64>,
    pub source: Option<String>,
    pub trace_id: Option<String>,
    pub sequence: Option<u64>,
    pub labels: HashMap<String, String>,
}

Operational metadata fields for an LNMP envelope

All fields are optional to provide flexibility. Applications should set fields based on their requirements:

• Timestamp: For temporal reasoning and freshness
• Source: For routing, multi-tenant, and trust scoring
• TraceID: For distributed tracing integration
• Sequence: For conflict resolution and ordering

Fields

timestamp: Option<u64>

Event timestamp in milliseconds since Unix epoch (UTC)

Recommended for all events. Used for:

• Temporal ordering
• Freshness/decay calculations
• Event replay

source: Option<String>

Source service/device/tenant identifier

Examples: “auth-service”, “sensor-12”, “tenant-acme”

Recommendation: Keep ≤ 64 characters

trace_id: Option<String>

Distributed tracing correlation ID

Compatible with W3C Trace Context and OpenTelemetry. Can hold full traceparent or just trace-id portion.

Recommendation: Keep ≤ 128 characters

sequence: Option<u64>

Monotonically increasing sequence number

Used for ordering and conflict resolution. Should increment for each version of the same entity.

labels: HashMap<String, String>

Extensibility labels (reserved for future use)

V1: Optional, implementations may ignore Future: tenant, environment, region, priority, etc.

Implementations

impl EnvelopeMetadata

pub fn new() -> Self

Creates a new empty metadata instance

pub fn is_empty(&self) -> bool

Returns true if all fields are None/empty

pub fn validate(&self) -> Result<()>

Validates metadata constraints

Checks:

• Source length ≤ 64 characters (warning threshold)
• TraceID length ≤ 128 characters (warning threshold)

Trait Implementations

impl Clone for EnvelopeMetadata

fn clone(&self) -> EnvelopeMetadata

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for EnvelopeMetadata

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for EnvelopeMetadata

fn default() -> EnvelopeMetadata

Returns the “default value” for a type.

impl PartialEq for EnvelopeMetadata

fn eq(&self, other: &EnvelopeMetadata) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for EnvelopeMetadata