Macro define_binary_input_node 

macro_rules! define_binary_input_node {
    (
        $(#[$meta:meta])*
        pub struct $name:ident {
            $($field:ident: $type:ty),* $(,)?
        }
        enum: $enum_variant:ident
        input: BinaryInputNode
    ) => { ... };
}

Define the macro for the dual-input plan node