Constant BUFFER_SIZE 

pub const BUFFER_SIZE: usize = f64::FORMATTED_SIZE; // 256usize

Available on crate features write-floats or write-integers only.

Maximum number of bytes required to serialize any number with default options to string.

Note that this value may be insufficient if digit precision control, exponent break points, or disabling exponent notation is used. Please read the documentation in lexical_write_float for more information.