See PR for background
We can introduce a SPI that allows 3rd party to plugin a custom implementation of the headers map. Then you can use the default, that 3rd party, or a case insensitive if the latter is sufficient. However typically HTTP/REST based protocols are case insensitive headers.
We should try to make it auto lookup from classpath using the factory finder which we do with others like the hystrix eip etc. Then we could have a camel-cedersoftware-java-util component which uses their implementation and Camel can then auto detect it from classpath and use it.