add
Adds a single metadata key/value pair to the current context.
Unlike Tags, which have a well defined value ordering, independent of the order in which values were added, context metadata preserves the order of addition. As such, it is not advised to add values for the same metadata key from multiple threads, since that may create non-deterministic ordering. It is recommended (where possible) to add metadata when building a new context, rather than adding it to context visible to multiple threads.