Name is the name of the gRPC Header to be matched.
If multiple entries specify equivalent header names, only the first
entry with an equivalent name MUST be considered for a match. Subsequent
entries with an equivalent header name MUST be ignored. Due to the
case-insensitivity of header names, "foo" and "Foo" are considered
equivalent.
GRPCHeaderMatch describes how to select a gRPC route by matching gRPC request headers.