message: Remove StructBuilder
  Summary: Dead code.
diff: @@ -59,7 +59,6 @@ use crate::values::comparison::equals_small_map;
  use crate::values::error::ValueError;
  use crate::values::layout::typed::string::StringValueLike;
  use crate::values::type_repr::StarlarkTypeRepr;
  -use crate::values::AllocValue;
  use crate::values::Freeze;
  use crate::values::FrozenValue;
  use crate::values::Heap;
  @@ -125,31 +124,6 @@ impl<'v, V: ValueLike<'v>> Display for StructGen<'v, V> {
  }
  }
  -/// A builder to create a `Struct` easily.
  -pub struct StructBuilder<'v>(&'v Heap, SmallMap<StringValue<'v>, Value<'v>>);
  -
  -impl<'v> StructBuilder<'v> {
  - /// Create a new [`StructBuilder`] with a given capacity.
  - pub fn with_capacity(heap: &'v Heap, capacity: usize) -> Self {
  - Self(heap, SmallMap::with_capacity(capacity))
  - }
  -
  - /// Create a new [`StructBuilder`].
  - pub fn new(heap: &'v Heap) -> Self {
  - Self(heap, SmallMap::new())
  - }
  -
  - /// Add an element to the underlying [`Struct`].
  - pub fn add(&mut self, key: &str, val: impl AllocValue<'v>) {
  - self.1.insert(self.0.alloc_str(key), self.0.alloc(val));
  - }
  -
  - /// Finish building and produce a [`Struct`].
  - pub fn build(self) -> Struct<'v> {
  - Struct { fields: self.1 }
  - }
  -}
  -
  impl<'v, V: ValueLike<'v> + 'v> StarlarkValue<'v> for StructGen<'v, V>
  where
  Self: ProvidesStaticType,
  