subscriber: fix missing space issue (#480)

Closes #474

Author: yaahc

tracing-subscriber/src/fmt/format/mod.rs

@@ -758,7 +758,7 @@ mod test {
         }
 
         let make_writer = || MockWriter::new(&BUF);
-        let expected = "\u{1b}[2mfake time\u{1b}[0m\u{1b}[32m INFO\u{1b}[0m tracing_subscriber::fmt::format::test: some ansi test\n";
+        let expected = "\u{1b}[2mfake time\u{1b}[0m \u{1b}[32m INFO\u{1b}[0m tracing_subscriber::fmt::format::test: some ansi test\n";
         test_ansi(make_writer, expected, true, &BUF);
     }
 

tracing-subscriber/src/fmt/time.rs

@@ -219,8 +219,8 @@ where
         write!(writer, "{}", style.suffix())?;
     } else {
         timer.format_time(writer)?;
-        write!(writer, " ")?;
     }
+    writer.write_char(' ')?;
     Ok(())
 }