Remove an unneeded explicit error conversion

src/postgres/connection/fetch.rs

@@ -7,7 +7,7 @@ pub fn fetch<'a>(
     conn: &'a mut PostgresRawConnection,
 ) -> impl Stream<Item = Result<PostgresRow, Error>> + 'a {
     async_stream::try_stream! {
-        conn.stream.flush().await.map_err(Error::Io)?;
+        conn.stream.flush().await.map_err(Error::from)?;
 
         while let Some(message) = conn.receive().await? {
             match message {

src/postgres/connection/mod.rs

@@ -34,9 +34,7 @@ pub struct PostgresRawConnection {
 impl PostgresRawConnection {
     async fn establish(url: &str) -> Result<Self, Error> {
         let url = Url::parse(url);
-        let stream = TcpStream::connect(&url.address(5432))
-            .await
-            .map_err(Error::Io)?;
+        let stream = TcpStream::connect(&url.address(5432)).await?;
 
         let mut conn = Self {
             stream: BufStream::new(stream),