# Functions
DecodeKeyValue returns k, v, nil.
FromContext is a wrapper for FromIncomingContext(ctx).
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.
NewContext is a wrapper for NewOutgoingContext(ctx, md).
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 ..
# Type aliases
MD is a mapping from metadata keys to values.