http4k / org.http4k.jsonrpc / MethodBindings / Manual / handler
fun <IN, OUT : Any> handler(paramsLens: Mapping<NODE, IN>, resultLens: Mapping<OUT, NODE>, fn: (IN) -> OUT): JsonRpcHandler<NODE, NODE>
fun <IN, OUT : Any> handler(paramsFieldNames: Set<String>, paramsLens: Mapping<NODE, IN>, resultLens: Mapping<OUT, NODE>, fn: (IN) -> OUT): JsonRpcHandler<NODE, NODE>
fun <OUT : Any> handler(resultLens: Mapping<OUT, NODE>, block: () -> OUT): JsonRpcHandler<NODE, NODE>