NgxStr::to_str renamed as_str

In Rust, the convention is that `to_` methods take ownership of self
(e.g. fn to_string(self) -> Self) whereas `as_` methods borrow self
(e.g. fn as_str(&self) -> &str).

Author: pchickey

examples/awssig.rs

@@ -282,7 +282,7 @@ http_request_handler!(awssigv4_header_handler, |request: &mut Request| {
     }
 
     let datetime = chrono::Utc::now();
-    let uri = match request.unparsed_uri().to_str() {
+    let uri = match request.unparsed_uri().as_str() {
         Ok(v) => format!("https://{}.{}{}", conf.s3_bucket, conf.s3_endpoint, v),
         Err(_) => return core::Status::NGX_DECLINED,
     };

src/core/string.rs

@@ -68,7 +68,7 @@ impl NgxStr {
     }
 
     /// Yields a `&str` slice if the [`NgxStr`] contains valid UTF-8.
-    pub fn to_str(&self) -> Result<&str, Utf8Error> {
+    pub fn as_str(&self) -> Result<&str, Utf8Error> {
         str::from_utf8(self.as_bytes())
     }