Function write_frame 

pub fn write_frame<W: Write>(
    writer: &mut W,
    body: &[u8],
) -> Result<usize, FramingError>

Write one v1 frame to writer.

The frame is laid out as [u8 framing_version=1][u32 LE body_length][body]. Returns the number of bytes written on success (5 + body.len()).

Errors

• FramingError::FrameTooLarge if body.len() exceeds MAX_FRAME_BYTES. The caller must not exceed MAX_HELLO_BYTES for Hello frames; this guard catches only the absolute ceiling.
• FramingError::Io for any other I/O error.