Add meaning

Signed-off-by: Stephen Wakely <fungus.humungus@gmail.com>

lib/vector-core/src/schema/meaning.rs

@@ -0,0 +1,17 @@
+//! Constants for commonly used semantic meanings.
+
+/// The service typically represents the application that generated the event.
+pub const SERVICE: &str = "service";
+
+/// The main text message of the event.
+pub const MESSAGE: &str = "message";
+
+/// The main timestamp of the event.
+pub const TIMESTAMP: &str = "timestamp";
+
+/// The hostname of the machine where the event was generated.
+pub const HOST: &str = "host";
+
+pub const SOURCE: &str = "source";
+pub const SEVERITY: &str = "severity";
+pub const TRACE_ID: &str = "trace_id";