add Pool::as_ptr, review feedback

Author: pchickey

src/async_/resolver.rs

@@ -259,10 +259,8 @@ impl<'a> Resolution<'a> {
                 .copy_to_nonoverlapping(sockaddr.cast(), addr.socklen as usize)
         };
 
-        let name = unsafe {
-            ngx_str_t::from_bytes(pool.as_ref() as *const _ as *mut _, addr.name.as_bytes())
-        }
-        .ok_or(Error::AllocationFailed)?;
+        let name = unsafe { ngx_str_t::from_bytes(pool.as_ptr(), addr.name.as_bytes()) }
+            .ok_or(Error::AllocationFailed)?;
 
         Ok(ngx_addr_t {
             sockaddr,

src/core/pool.rs

@@ -145,6 +145,12 @@ impl Pool {
         Pool(NonNull::new_unchecked(pool))
     }
 
+    /// Expose the underlying `ngx_pool_t` pointer, for use with `ngx::ffi`
+    /// functions.
+    pub fn as_ptr(&self) -> *mut ngx_pool_t {
+        self.0.as_ptr()
+    }
+
     /// Creates a buffer of the specified size in the memory pool.
     ///
     /// Returns `Some(TemporaryBuffer)` if the buffer is successfully created, or `None` if