Solve PR comments.

* Move meta to meta_struct.
* Add doc to read_map_len.

trace-utils/src/msgpack_decoder/decode/map.rs

@@ -51,6 +51,22 @@ where
     Ok(map)
 }
 
+/// Reads map length from the buffer
+///
+/// # Arguments
+///
+/// * `buf` - A reference to the Bytes containing the encoded map data.
+///
+/// # Returns
+///
+/// * `Ok(usize)` - Map length.
+/// * `Err(DecodeError)` - An error if the decoding process fails.
+///
+/// # Errors
+///
+/// This function will return an error if:
+/// - The buffer does not contain a map.
+/// - There is an error reading from the buffer.
 #[inline]
 pub fn read_map_len(buf: &mut &[u8]) -> Result<usize, DecodeError> {
     match decode::read_marker(buf)

trace-utils/src/msgpack_decoder/decode/mod.rs

@@ -3,7 +3,7 @@
 
 pub mod error;
 pub mod map;
-pub mod meta;
+pub mod meta_struct;
 pub mod metrics;
 pub mod number;
 pub mod span_link;

trace-utils/src/msgpack_decoder/v04/span.rs

@@ -7,7 +7,7 @@ use crate::msgpack_decoder::decode::span_link::read_span_links;
 use crate::msgpack_decoder::decode::string::{
     read_nullable_str_map_to_bytes_strings, read_nullable_string_bytes, read_string_ref,
 };
-use crate::msgpack_decoder::decode::{meta::read_meta_struct, metrics::read_metrics};
+use crate::msgpack_decoder::decode::{meta_struct::read_meta_struct, metrics::read_metrics};
 use crate::span::v04::{Span, SpanKey};
 use tinybytes::Bytes;