SpanKind(value)Type of span. Can be used to specify additional relationships between spans in addition to a parent/child relationship.
Values: SPAN_KIND_UNSPECIFIED (0): Unspecified. Do NOT use as default. Implementations MAY assume SpanKind.INTERNAL to be default. INTERNAL (1): Indicates that the span is used internally. Default value. SERVER (2): Indicates that the span covers server-side handling of an RPC or other remote network request. CLIENT (3): Indicates that the span covers the client-side wrapper around an RPC or other remote request. PRODUCER (4): Indicates that the span describes producer sending a message to a broker. Unlike client and server, there is no direct critical path latency relationship between producer and consumer spans (e.g. publishing a message to a pubsub service). CONSUMER (5): Indicates that the span describes consumer receiving a message from a broker. Unlike client and server, there is no direct critical path latency relationship between producer and consumer spans (e.g. receiving a message from a pubsub service subscription).