Remove the unsafe Send impl of the iterators

Author: Kerollmops

heed/src/iterator/iter.rs

@@ -208,9 +208,6 @@ impl<KC, DC, IM> fmt::Debug for RoIter<'_, KC, DC, IM> {
     }
 }
 
-/// A `RoIter` is `Send` only if the `RoTxn` is.
-unsafe impl<KC, DC, IM> Send for RoIter<'_, KC, DC, IM> {}
-
 /// A read-write iterator structure.
 pub struct RwIter<'txn, KC, DC, IM = MoveThroughDuplicateValues> {
     cursor: RwCursor<'txn>,
@@ -557,8 +554,6 @@ impl<KC, DC, IM> fmt::Debug for RoRevIter<'_, KC, DC, IM> {
     }
 }
 
-unsafe impl<KC, DC, IM> Send for RoRevIter<'_, KC, DC, IM> {}
-
 /// A reverse read-write iterator structure.
 pub struct RwRevIter<'txn, KC, DC, IM = MoveThroughDuplicateValues> {
     cursor: RwCursor<'txn>,

heed/src/iterator/prefix.rs

@@ -200,8 +200,6 @@ impl<KC, DC, C, IM> fmt::Debug for RoPrefix<'_, KC, DC, C, IM> {
     }
 }
 
-unsafe impl<KC, DC, IM> Send for RoPrefix<'_, WithoutTls, KC, DC, IM> {}
-
 /// A read-write prefix iterator structure.
 pub struct RwPrefix<'txn, KC, DC, C = DefaultComparator, IM = MoveThroughDuplicateValues> {
     cursor: RwCursor<'txn>,
@@ -589,8 +587,6 @@ impl<KC, DC, C, IM> fmt::Debug for RoRevPrefix<'_, KC, DC, C, IM> {
     }
 }
 
-unsafe impl<KC, DC, IM> Send for RoRevPrefix<'_, WithoutTls, KC, DC, IM> {}
-
 /// A reverse read-write prefix iterator structure.
 pub struct RwRevPrefix<'txn, KC, DC, C = DefaultComparator, IM = MoveThroughDuplicateValues> {
     cursor: RwCursor<'txn>,

heed/src/iterator/range.rs

@@ -199,8 +199,6 @@ impl<KC, DC, C, IM> fmt::Debug for RoRange<'_, KC, DC, C, IM> {
     }
 }
 
-unsafe impl<KC, DC, C, IM> Send for RoRange<'_, KC, DC, C, IM> {}
-
 /// A read-write range iterator structure.
 pub struct RwRange<'txn, KC, DC, C = DefaultComparator, IM = MoveThroughDuplicateValues> {
     cursor: RwCursor<'txn>,
@@ -637,8 +635,6 @@ impl<KC, DC, C, IM> fmt::Debug for RoRevRange<'_, KC, DC, C, IM> {
     }
 }
 
-unsafe impl<KC, DC, C, IM> Send for RoRevRange<'_, KC, DC, C, IM> {}
-
 /// A reverse read-write range iterator structure.
 pub struct RwRevRange<'txn, KC, DC, C = DefaultComparator, IM = MoveThroughDuplicateValues> {
     cursor: RwCursor<'txn>,