API-Rust.md: Use the addr_of_mut!() macro

Signed-off-by: Andrew Clayton <a.clayton@nginx.com>

Author: ac000

API-Rust.md

@@ -492,7 +492,7 @@ static mut REQUEST_BUF: *mut u8 = null_mut();
 */ ... */
 #[no_mangle]
 pub extern "C" fn uwr_request_handler(addr: *mut u8) -> i32 {
-    let ctx: *mut luw_ctx_t = unsafe { &mut CTX };
+    let ctx: *mut luw_ctx_t = unsafe { addr_of_mut!(CTX) };
 
     if unsafe { REQUEST_BUF.is_null() } {
         uwr_init_ctx(ctx, addr, 0 /* Response offset */);
@@ -507,7 +507,7 @@ pub extern "C" fn uwr_request_handler(addr: *mut u8) -> i32 {
          */
         uwr_set_req_buf(
             ctx,
-            unsafe { &mut REQUEST_BUF },
+            unsafe { addr_of_mut!(REQUEST_BUF) },
             LUW_SRB_APPEND | LUW_SRB_ALLOC | LUW_SRB_FULL_SIZE,
         );
     } else {
@@ -811,7 +811,7 @@ Example
 ```Rust
 #[no_mangle]
 pub extern "C" fn uwr_request_handler(addr: *mut u8) -> i32 {
-    let ctx: *mut luw_ctx_t = unsafe { &mut CTX };
+    let ctx: *mut luw_ctx_t = unsafe { addr_of_mut!(CTX) };
 
     if unsafe { REQUEST_BUF.is_null() } {
         uwr_init_ctx(ctx, addr, 0 /* Response offset */);
@@ -826,7 +826,7 @@ pub extern "C" fn uwr_request_handler(addr: *mut u8) -> i32 {
          */
         uwr_set_req_buf(
             ctx,
-            unsafe { &mut REQUEST_BUF },
+            unsafe { addr_of_mut!(REQUEST_BUF) },
             LUW_SRB_APPEND | LUW_SRB_ALLOC | LUW_SRB_FULL_SIZE,
         );
     } else {
@@ -868,14 +868,18 @@ Example
 
 ```Rust
 pub extern "C" fn uwr_request_handler(addr: *mut u8) -> i32 {
-    let ctx: *mut luw_ctx_t = unsafe { &mut CTX };
+    let ctx: *mut luw_ctx_t = unsafe { addr_of_mut!(CTX) };
     let mut f;
     let bytes_wrote: isize;
     let mut total = unsafe { TOTAL_BYTES_WROTE };
 
     if total == 0 {
         uwr_init_ctx(ctx, addr, 0);
-        uwr_set_req_buf(ctx, unsafe { &mut REQUEST_BUF }, LUW_SRB_NONE);
+        uwr_set_req_buf(
+            ctx,
+            unsafe { addr_of_mut!(REQUEST_BUF) },
+            LUW_SRB_NONE
+        );
 
         f = File::create("/var/tmp/large-file.dat").unwrap();
     } else {