Function get_nullable_array_len 

pub fn get_nullable_array_len<B: Buf>(
    buf: &mut B,
    flexible: bool,
) -> Result<Option<usize>, ProtocolError>

Reads a nullable array length. Returns None when the encoded value is null, which is −1 for non-flexible versions and 0 for flexible versions.

Errors

Returns the underlying protocol error when input is truncated, contains an invalid length or tag, or cannot be encoded for the selected version.