# Functions
AppendToOutgoingContext returns a new context with the provided kv merged with any existing metadata in the context.
DecodeKeyValue returns k, v, nil.
FromIncomingContext returns the incoming metadata in ctx if it exists.
FromOutgoingContext returns the outgoing metadata in ctx if it exists.
Join joins any number of mds into a single MD.
New creates an MD from a given key-value map.
NewIncomingContext creates a new context with incoming md attached.
NewOutgoingContext creates a new context with outgoing md attached.
Pairs returns an MD formed by the mapping of key, value ..
ValueFromIncomingContext returns the metadata value corresponding to the metadata key from the incoming metadata if it exists.
# Type aliases
MD is a mapping from metadata keys to values.