Function bincode_core::serialize_size

pub fn serialize_size<T: Serialize + ?Sized, O: Options>(
    value: &T, 
    options: O
) -> Result<usize, SerializeError<()>>

Return the size that serializing a given T type would need to be stored. This is an optimized version of getting the length of the writer after it’s done writing.

let mut buffer = [0u8; 1000];
let mut writer = BufferWriter::new(&mut buffer);
let options = DefaultOptions::new();

let value = "your data structure goes here";

serialize(value, &mut writer, options).unwrap();
let written_len = writer.written_len();

let measured_len = serialize_size(value, options).unwrap();

assert_eq!(written_len, measured_len);

But without actually writing to memory