Implement bounded Binary LLSD codec

tests/compat/tests/structured_data.rs

@@ -17,7 +17,7 @@ use libremetaverse_compat_tests::{assert_bytes_eq, assert_close};
 use libremetaverse_structured_data::{OSD, OSDParser, OSDType};
 use libremetaverse_types::compat::{StringReader, Uri, Utf16CodeUnit};
 use libremetaverse_types::{UUID, Utils};
-use std::io::{Cursor, Read, Write};
+use std::io::{Cursor, Read, Seek, SeekFrom, Write};
 use std::sync::{Arc, Mutex};
 use std::time::{Duration, SystemTime, UNIX_EPOCH};
 
@@ -173,6 +173,12 @@ impl Write for SharedCursor {
     }
 }
 
+impl Seek for SharedCursor {
+    fn seek(&mut self, position: SeekFrom) -> std::io::Result<u64> {
+        self.0.lock().expect("cursor lock").seek(position)
+    }
+}
+
 const BINARY_STRING_CONTENT: &[u8] = b"testing a simple binary conversion for this string\n\r";
 const BINARY_NESTED_VALUE: &[u8] = &[
     0x5b, 0, 0, 0, 3, 0x7b, 0, 0, 0, 2, 0x6b, 0, 0, 0, 4, b't', b'e', b's', b't', 0x73, 0, 0, 0, 4,