Make CompoundBody consumption past end idempotent

implementations/rust/src/value/reader.rs

@@ -22,6 +22,7 @@ pub struct CompoundBody {
 pub enum CompoundLimit {
     Counted(usize),
     Streaming,
+    Finished,
 }
 
 impl CompoundBody {
@@ -38,6 +39,7 @@ impl CompoundBody {
             CompoundLimit::Counted(ref mut n) =>
                 if *n == 0 {
                     read.close_compound_counted(self.minor)?;
+                    self.limit = CompoundLimit::Finished;
                     Ok(false)
                 } else {
                     *n = *n - 1;
@@ -45,6 +47,8 @@ impl CompoundBody {
                 },
             CompoundLimit::Streaming =>
                 Ok(!read.close_compound_stream(self.minor)?),
+            CompoundLimit::Finished =>
+                Ok(false),
         }
     }