windows7: Silence false positive truncation warning.

Author: briansmith

src/windows7.rs

@@ -27,7 +27,9 @@ pub fn getrandom_inner(dest: &mut [MaybeUninit<u8>]) -> Result<(), Error> {
     // Prevent overflow of u32
     let chunk_size = usize::try_from(i32::MAX).expect("Windows does not support 16-bit targets");
     for chunk in dest.chunks_mut(chunk_size) {
-        let ret = unsafe { RtlGenRandom(chunk.as_mut_ptr().cast::<c_void>(), chunk.len() as u32) };
+        #[allow(clippy::cast_possible_truncation)]
+        let chunk_len = chunk.len() as u32;
+        let ret = unsafe { RtlGenRandom(chunk.as_mut_ptr().cast::<c_void>(), chunk_len) };
         if ret != TRUE {
             return Err(Error::WINDOWS_RTL_GEN_RANDOM);
         }