Function igShadeVertsLinearColorGradientKeepAlpha 

pub unsafe extern "C" fn igShadeVertsLinearColorGradientKeepAlpha(
    draw_list: *mut ImDrawList,
    vert_start_idx: c_int,
    vert_end_idx: c_int,
    gradient_p0: ImVec2_c,
    gradient_p1: ImVec2_c,
    col0: ImU32,
    col1: ImU32,
)