Added FromStream + Extend for BTreeSet

Author: sunjay

src/collections/btree_set/extend.rs

@@ -0,0 +1,16 @@
+use std::pin::Pin;
+use std::collections::BTreeSet;
+
+use crate::prelude::*;
+use crate::stream::{Extend, IntoStream};
+
+impl<T: Ord> Extend<T> for BTreeSet<T> {
+    fn stream_extend<'a, S: IntoStream<Item = T> + 'a>(
+        &'a mut self,
+        stream: S,
+    ) -> Pin<Box<dyn Future<Output = ()> + 'a>> {
+        Box::pin(stream.into_stream().for_each(move |item| {
+            self.insert(item);
+        }))
+    }
+}

src/collections/btree_set/from_stream.rs

@@ -0,0 +1,24 @@
+use std::pin::Pin;
+use std::collections::BTreeSet;
+
+use crate::stream::{Extend, FromStream, IntoStream};
+
+impl<T: Ord> FromStream<T> for BTreeSet<T> {
+    #[inline]
+    fn from_stream<'a, S: IntoStream<Item = T>>(
+        stream: S,
+    ) -> Pin<Box<dyn core::future::Future<Output = Self> + 'a>>
+    where
+        <S as IntoStream>::IntoStream: 'a,
+    {
+        let stream = stream.into_stream();
+
+        Box::pin(async move {
+            pin_utils::pin_mut!(stream);
+
+            let mut out = BTreeSet::new();
+            out.stream_extend(stream).await;
+            out
+        })
+    }
+}

src/collections/btree_set/mod.rs

@@ -0,0 +1,7 @@
+//! The Rust B-Tree Set
+
+mod extend;
+mod from_stream;
+
+#[doc(inline)]
+pub use std::collections::BTreeSet;

src/collections/mod.rs

@@ -7,8 +7,10 @@ pub mod vec_deque;
 pub mod hash_map;
 pub mod hash_set;
 pub mod btree_map;
+pub mod btree_set;
 
 pub use vec_deque::VecDeque;
 pub use hash_map::HashMap;
 pub use hash_set::HashSet;
 pub use btree_map::BTreeMap;
+pub use btree_set::BTreeSet;