`sig
val http_trials : int Pervasives.ref
val http_user : string Pervasives.ref
val http_password : string Pervasives.ref
val http_get_message : string -> Http_client.http_call
val http_head_message : string -> Http_client.http_call
val http_post_message :
string -> (string * string) list -> Http_client.http_call
val http_put_message : string -> string -> Http_client.http_call
val http_delete_message : string -> Http_client.http_call
val http_get : string -> string
val http_post : string -> (string * string) list -> string
val http_put : string -> string -> string
val http_delete : string -> string
val http_verbose : unit -> unit
end`