improve utf8 init validity

src/array/boolean/mutable.rs

@@ -170,7 +170,7 @@ impl MutableBooleanArray {
     }
 
     fn init_validity(&mut self) {
-        let mut validity = MutableBitmap::new();
+        let mut validity = MutableBitmap::with_capacity(self.values.capacity());
         validity.extend_constant(self.len(), true);
         validity.set(self.len() - 1, false);
         self.validity = Some(validity)

src/array/list/mutable.rs

@@ -177,7 +177,7 @@ impl<O: Offset, M: MutableArray> MutableListArray<O, M> {
     fn init_validity(&mut self) {
         let len = self.offsets.len() - 1;
 
-        let mut validity = MutableBitmap::new();
+        let mut validity = MutableBitmap::with_capacity(self.offsets.capacity());
         validity.extend_constant(len, true);
         validity.set(len - 1, false);
         self.validity = Some(validity)

src/array/primitive/mutable.rs

@@ -217,7 +217,7 @@ impl<T: NativeType> MutablePrimitiveArray<T> {
     }
 
     fn init_validity(&mut self) {
-        let mut validity = MutableBitmap::new();
+        let mut validity = MutableBitmap::with_capacity(self.values.capacity());
         validity.extend_constant(self.len(), true);
         validity.set(self.len() - 1, false);
         self.validity = Some(validity)

src/array/utf8/mutable.rs

@@ -152,11 +152,10 @@ impl<O: Offset> MutableUtf8Array<O> {
     }
 
     fn init_validity(&mut self) {
-        self.validity = Some(MutableBitmap::from_trusted_len_iter(
-            std::iter::repeat(true)
-                .take(self.len() - 1)
-                .chain(std::iter::once(false)),
-        ))
+        let mut validity = MutableBitmap::with_capacity(self.offsets.capacity());
+        validity.extend_constant(self.len(), true);
+        validity.set(self.len() - 1, false);
+        self.validity = Some(validity);
     }
 
     /// Converts itself into an [`Array`].