Function emit_write 

pub fn emit_write(
    w: &mut CodeWriter,
    access: &str,
    ty: &ResolvedType,
    enc: &FieldEncoding,
    registry: &TypeRegistry,
    writer: &str,
)

Emit code to write a value to a BitWriter.

access is the TypeScript expression for the value. writer is the variable name of the BitWriter (e.g. “w” or “payloadW”).