Marking platformwriter public

Author: pruthvikar

src/lib.rs

@@ -256,7 +256,7 @@ impl Config {
     }
 }
 
-struct PlatformLogWriter<'a> {
+pub struct PlatformLogWriter<'a> {
     #[cfg(target_os = "android")] priority: LogPriority,
     #[cfg(not(target_os = "android"))] priority: Level,
     len: usize,