``` data class HeaderName(val name: String) { ...

# kotlin-fuel

[Derk-Jan Karrenbeld]

data class HeaderName(val name: String) {
        private val normalized = name.toUpperCase()
        override fun hashCode(): Int {
            return normalized.hashCode()
        }

        override fun equals(other: Any?): Boolean {
            return (other is HeaderName) && other.normalized === normalized
        }
    }

HeaderName(key) can now be used as HashMap accessor and it will JustWork™, because HashMap uses hashCode.