wasmify-sophia : Add exported methods

wasmify-sophia_Add_Exported_Methods.md

https://github.com/BruJu/wasmify-sophia

wasm_bindgen_dataset!(TreedDataset, "TreedDataset", SophiaExportDataset);

+use crate::wrapping::*;
+
+#[wasm_bindgen(js_class="TreedDataset")]
+impl SophiaExportDataset {
+    pub fn get_nb_underlying(&self) -> usize {
+        self.base.dataset().get_number_of_underlying_trees()
+    }
+}

And that's it.

Explanation

• The third argument is the name of the class that will be exported
• Rust enables you to define multiple impl block
• base is the adapter, base.dataset() is the Sophia compliant dataset