Constant GET_ADDRS_MAX_BYTES 

pub const GET_ADDRS_MAX_BYTES: u64 = 57;

GetAddrs message fields size:

• max = 4
• transports = 1 (vec_len) + 4 + 4 + 4 + 4 + 4 + 8 + 8 + 8 + 8 = 53

Transports is list of all transports to be shared specified in protocol_address.