Pass list to UDF

I'd like to have a UDF that works as a basic 'a is in array/list' function. Since I do not know the size of a list, I cannot put a "list" option in handler Info function, because it will add a number of arguments restriction. Is there a way to specify a property method on my handler? I've seen in source code that there is usage of reflection to search for property methods, but I don't understand how it works so far.

How I want UDF to be called:
```
var list = ['a', 'b', '42']
...
@inList()
.value('value')
.list(list)
...
```
Current blocker is here
```golang
func (*inListHandler) Info() (*agent.InfoResponse, error) {
info := &agent.InfoResponse{
Wants: agent.EdgeType_STREAM,
Provides: agent.EdgeType_STREAM,
Options: map[string]*agent.OptionInfo{
"value": {ValueTypes: []agent.ValueType{agent.ValueType_STRING}},
"list": {ValueTypes: []agent.ValueType{agent.ValueType_STRING, agent.ValueType_STRING....how many of these should I put?}},
},
}
return info, nil
}
```

Start by reading the inListHandler Info() method and the UDF handler documentation or entry points related to agent.OptionInfo. Trace the existing reflection-based property-method handling mentioned in the issue. Done should establish a supported way to pass a variable-length list to a UDF and document or test the resulting call form.

Written by the indexing model from the issue text.