"max-post-size" => {
                "type" => LONG,
                "description" => "The maximum size of a post that will be accepted, in bytes.",
                "expressions-allowed" => true,
                "required" => false,
                "nillable" => true,
                "default" => 10485760L,
                "unit" => "BYTES",
                "min" => 1L,
                "max" => 2147483647L,
                "access-type" => "read-write",
                "storage" => "configuration",
                "restart-required" => "no-services"
            },

[standalone@localhost:9990 /]  /subsystem=undertow/server=default-server/http-listener=default:write-attribute(name=max-post-size, value=9223372036854775807)
{
    "outcome" => "failed",
    "failure-description" => "WFLYCTL0097: Wrong type for 'max-post-size'. Expected [INT] but was STRING. Couldn't convert \"9223372036854775807\" to [INT]",
    "rolled-back" => true,
    "response-headers" => {"process-state" => "reload-required"}
}