iter: remove the truncated case

fixes test::write_many

src/error.rs

@@ -20,7 +20,6 @@ impl<B> From<WriteError<B>> for Error<B> {
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub enum ReadError {
-    Truncated { offset: usize },
     InvalidSize { offset: usize, size: usize },
     MissingSeparator { offset: usize },
     Utf8Error(str::Utf8Error),
@@ -29,8 +28,6 @@ pub enum ReadError {
 impl fmt::Display for ReadError {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match self {
-            &ReadError::Truncated { offset }=>
-                write!(f, "truncated record at offset {}", offset),
             &ReadError::InvalidSize { offset, size } =>
                 write!(f, "invalid record size {} at offset {}", size, offset),
             &ReadError::MissingSeparator { offset } =>

src/iter.rs

@@ -20,7 +20,7 @@ impl<'a> Iterator for Iter<'a> {
         let data = &self.data[self.offset..];
 
         if data.len() < 4 {
-            return Some(Err(ReadError::Truncated { offset: self.offset }))
+            return None;
         }
 
         let record_size = BigEndian::read_u32(data) as usize;