Function signal_buffer_append 

pub unsafe extern "C" fn signal_buffer_append(
    buffer: *mut signal_buffer,
    data: *const u8,
    len: usize,
) -> *mut signal_buffer

Append the provided data to an existing buffer. Note: The underlying buffer is only expanded by an amount sufficient to hold the data being appended. There is no additional reserved space to reduce the need for memory allocations.

@param buffer the existing buffer to append to @param data pointer to the start of the data @param len length of the data @return pointer to the updated buffer, or 0 on failure