Function write_extensions 

pub fn write_extensions<W: Write>(
    writer: &mut W,
    version: u8,
    extensions: Option<&[u8]>,
) -> Result<(), AescryptError>

Writes the v3 extension-block section, terminated by a zero-length record.

If extensions is Some(bytes), those bytes are written verbatim. If None, the canonical “no extensions” terminator [0x00, 0x00] is written.

Format

Each extension is a u16 big-endian length followed by length payload bytes; a length of 0 ends the section. When extensions is Some, the caller is responsible for emitting any payload extensions and the trailing [0x00, 0x00] terminator.

Errors

• AescryptError::UnsupportedVersion — version < 3.
• AescryptError::Io — writer returned an error.